Windows only: Remember the Milk is a powerful task manager, but most office work puts Outlook in front of you. Now you can bridge your Outlook and RTM tasks with MilkSync, a free download for RTM Pro customers (and 15-day trial for everyone else).
MilkSync looks like it can be either your set-and-forget total sync tool, or can be very selective in which lists make it back and forth from your work setup to your cloud-based RTM list. It's handy for RTM addicts, but also for anyone who finds it hard to find just the right Outlook-connected app for their iPhone or Android or other device—lots of RTM apps, including the official versions, are available for many platforms.
MilkSync is a free download for Windows systems running Outlook 2003, 2007, and 2010.
MilkSync for Microsoft® Outlook [Remember The Milk]