For Barcino -
There are bunch of ways to set up Outlook to use with GTD.
I'm tweaking my method all of the time.

You might want to review this thread:
http://board.43folders.com/showthread.php?t=278

For Claire -
Here's a link on how to create a new folder (as a Contacts type folder) and use that to track Projects.
http://home.comcast.net/~whkratz/id3.htm
I tried but it did not do the trick for me.
I simply have a Paper Folder for each "Project" to hold backup documents, and I use Word / and MS Project for outlining tasks and reporting status.
I use Categories in Outlook Tasks to associate "Next Action" tasks to a specific project. And add new Task entries from my Project outline when the current Next Action for a given project is completed.