Firefox with Greasemonkey only: The Google Contacts Autocomplete user script adds a drop-down of your Gmail contacts on any web-based email form where you'd enter an address. You must be signed into your Gmail account for the script to work; once it's installed, just start typing into an email text field to get search-as-you-type results from your Gmail address book. The first day or so it was installed, the script did nothing for me—then it magically started working (see screenshot)—so your mileage may vary. When it is working, this is a nifty way to access your contacts quickly and easily. The Google Contacts Autocomplete user script is a free download and requires Firefox with Greasemonkey. Thanks, Matt!