It's been a while since we've heard from some of our favourite to-do apps, Wunderlist and Any.Do, which means it's a perfect time for a fresh look at both apps. Both are still some of the best, cross-platform, free to-do managers available, but let's see how far they have come.

When you have several meetings packed into one day, you almost always end up with gaps between each one. Even though these gaps are often about 30 minutes, they seem like they aren't long enough to get anything done. Keep an ongoing list of small tasks to make the most of them.

Mail Pilot is an admirable email app for iOS that turns your emails into to-dos, and if you want to check it out on OS X, you can do so now for free.

The iPhone-toting blogger at Minddriven says that the cameraphone is often within reach when he wants to capture a task to his to-do list—so he snaps a photo of what needs to be done instead of writing it down. If he needs to buy more toothpaste, he snaps a photo of the empty tube and stores it in the to-do album. When he buys new toothpaste? He deletes the photo. Definitely a nice way to track tasks for the more visual folks among us, though I wonder what happens when he thinks of the empty toothpaste tube but isn't standing in front of it.

Windows/Mac/Linux (Thunderbird): Harness the to-do-managing power of Remember the Milk from inside your mail reader with an alpha extension for Thunderbird. Once installed and authenticated with your RTM account, the task manager provided by the Lightning extension will have bi-directional access to your tasks, which you can add, delete, modify, and prioritise from inside your mail manager. Hit the video above to see a few of the things you can do with the extension, and hit the via link below for step-by-step installation instructions. Remember the Milk Provider extension is a free download, but requires a free Mozilla Add-Ons account to download, needs the Lightning calendar extension, and works wherever Thunderbird does.

Email-based digital personal assistant Sandy can be a really helpful manager for to-do lists and calendar appointments, but only if you don't mind composing new messages for every change. Reader Wyatt writes in with a quicker way to get Sandy's attention, using Outlook, Windows keystroke launcher Launchy, and a custom line for its built-in Runner plugin. Create a new Runner command named "Sandy" or something similar and point it to the location of Outlook's executable file, but add the following switches at the end (substituting your Sandy username):

/c ipm.note /m [email protected]yourname.iwantsandy.com

Want to customise the resulting instant email further? Here's a guide to more Outlook switches. Gmail fans can also piece together a similar quick-launch Sandy through a Gmail script for Launchy. (Original Sandy post).

For the next week and a half, readers are submitting their best life hack for a chance to win an autographed copy of our new book, Upgrade Your Life. Reader Denis wanted to embed a to-do list on his Windows desktop, and came up with a no-install solution:

Mac OS X Leopard only: Despite its unfortunate name, task manager Anxiety is a slick, good-looking, lightweight way to keep track of your to-do lists. Since Leopard now includes a "calendar store," or central repository of tasks from both iCal and Mail.app, Anxiety taps into those lists and displays the items on your desktop. Add, change or check off a to-do in Anxiety, iCal or Mail? And the info updates across all three applications. Neat. Anxiety is a free download (donations encouraged) for Mac OS X Leopard only.

Windows and Mac OS X: Task manager Sciral Consistency tracks to-do's that don't have hard and fast deadlines, but need to be done on a regular basis. Keep on top of when it's time to clean out the fish tank, balance your checkbook, get a haircut, an oil change, a teeth cleaning, or simply when too much time has passed since you called Mom with Consistency, which creates a time-based horizontal grid of days. You enter a task and the minimum and maximum amount of time that should pass between each time you do it, and Consistency marks which tasks need doing and which you've still got time on for a given day. Sciral Consistency is a free download (with limited use) for Windows and Mac OS; a licence will set you back $25.

If you live out of your inbox and don't have the luxury of a human assistant, check out newly launched webapp Sandy, an information tracker you interact with via email. Register for a free account and you'll get an email address you can send your to-do's, contacts, bookmarks, notes, and appointments to in keyworded messages. Sandy receives the email, parses, stores, and organises the information, and emails you back reminders and agendas only when you need 'em.

Windows only: Free-for-now to-do list application Tudumo is styled for those aiming at Getting Things Done and geared to keyboard shortcut enthusiasts. All the basic to-do features like tags, due dates, action descriptions are present, but hitting one shortcut (Ctrl-Windows-T) from anywhere to add a quick item is a nice way to keep your list front-and-center. Tudumo also features quick as-you-type search and drag-and-drop tagging. Tudumo is a free download while it's still in beta for Windows XP, 2000 and Vista and requires the Microsoft .NET 2.0 platform be installed.

One thing that Windows and Outlook have always had up on the Mac's default email and calendar apps, Mail and iCal, is Outlook's integrated to-do manager. Today the game changes. Leopard's new Mail and iCal applications introduce their own take on the email- and calendar-integrated to-do list. So now the question is: Is it any good? The answer: Yes. And no. But probably yes. The To Do manager, at the moment, is a bit of a mishmash of some very good and a few bad—or at least unrealized—features.

The Mail.app To Do feature resides in the Reminders panel of the Mail sidebar below Notes. Mail to-dos can be organized by due date, priority (high, medium, low, or none), title, and calendar (that's right, they also integrate with iCal). You can create a new to-do in a couple of ways.

First, click the To Do button in the toolbar. You'll jump straight to the To Do window, where you can enter the details of a new item. Alternately, you can create your to-dos from Notes (another new feature in Mail). Once you've written a note, you can convert any line of the note or the entire note into one or several to-dos. The strange-yet-interesting thing about to-do notes is that the new to-do will appear in the To Do screen as well as the note, and you can check it off in either place. In fact, you can check off to-dos in a third place as well: iCal.

iCal's organisation of to-dos is much more convenient than Mail's To Do view, if only for its more prominent focus on due dates and priorities and its sidebar display (so you can view to-dos along with application content). To get a look at your to-do list within iCal, just click the thumb tack button on the bottom right of iCal. From there, you can check off your to-dos, re-prioritise, or change other information by double-clicking the item.

My biggest gripe about Mail's implementation of to-dos is that you can't create a new to-do from an email (or anything else, for that matter) via drag and drop. Also, the Notes integration is completely bizzare since Apple dropped the ball on supporting iPhone-to-Mail syncing of notes. As is, it comes off like a pointless appendage to Mail.app.

Another little bug I ran into: I couldn't change the due date of a to-do from Mail when iCal was open. Instead, I had to change the date inside iCal—though I would assume this will be fixed with an update.

In the end, to-do lovers have a promising addition to Apple's email and calendar apps, but considering the breadth of full-featured alternative to-do list managers that have popped up in the absence of one from Apple (including ones that integrate with iCal in one way or another), it's tough to say whether Leopard's To Do feature will catch on for the hardcore list keeper.

Mac OS X only: To-do lists are a great way to keep your mind and projects organized, but messing with your program or web-based list's features defeats the purpose. Enter TaskPaper, a seriously simple task manager from the developers of the distraction-free word processor Writeroom. TaskPaper, now in a finished 1.0 version, keeps it simple with text-based lists that can be modified by TextEdit or any other editor. The interface keeps the focus on projects, tasks and checking them off, but tabbed windows and context browsing allow for bigger-picture views. TaskPaper is available as a free trial for Mac OS X 10.4 or later, but a licence will set you back $18.95. If you're looking to get serious with to-do lists, check out Gina's guide to the art of the doable to-do list, or get even more streamlined with paper lists.

Tech site the How-To Geek puts Microsoft Outlook 2007's To-Do Bar through the paces, demonstrating how to create, categorise, complete, organise, and flag tasks using it. I haven't used Outlook on a daily basis since my escape to the freelance life, but most people with office jobs live in it. Are you using Outlook's To-Do manager to GTD? What do you love or hate about it? Let us know in the comments.

It's no wonder the majority of Lifehacker readers voted Remember the Milk the best web-based task manager out there. Remember the Milk's got all the best features modern webapps have to offer: email/SMS/IM integration, tagging, advanced search, keyboard shortcuts and even offline access with Google Gears. Chances are you work across several computers and need a single, always-accessible place to consolidate your work, personal, school, and family to-do's. Remember the Milk is a great way to do just that. Let's take a closer look at Remember the Milk's basic and more advanced features.

Instantly share files, notes, and photos with Stixy, an online bulletin board web application. An information manager at its core, Stixy gives you plenty of control over tasks, appointments, photos, notes, and bookmarks, and you can share your bulletin board with family and friends. There is no limitation on the size of a workspace but each file is capped at 10MB. Also, for now, there's no way to view many files (PDFs, DOCs, videos) without downloading them locally—but hopefully they'll implement functionality to support accessing these files server-side. However, for collaboration, Stixy makes it easy to share many files and store files online.