If you code (or even if you don't) check out the eclipse plug-in Myln (http://www.eclipse.org/mylyn/) and using Trac (http://trac.edgewall.org/) as a task repository (there are plenty of good cheap hosts like projectlocker.com). There is a great extension to it called Tasktop Pro that lets you use a gmail label as a task repository too.
The great thing about Myln is that it is "context based" - ie it filters tasks to the work you're doing at the time, and looks after opening all the related resources needed for it.
Google each of trac, myln, tasktop pro and projectlocker to see examples and how other people use them.
