I read David Allen's Getting Things Done a while ago and was impressed by the clarity and simplicity of the system. In his book he talks about the first step - that sweep - of being a requirement to start. That was too much of a hurdle for me and I have languished in my unorganized state since then.
Today, I came across an interesting talk by a guy named Merlin Mann who spoke at a meeting of SF Chapter of ACM SIGCHI. If you have any interest at all in this subject I recommend the 40 minutes it takes to listen to this. It is entertaining and insightful. He talks about Getting Things Done in a really accessible way and has some great ideas on small nudges you can take in your life to make you more effective.
Merlin Mann also has a great website that focuses on "geek productivity" and has some fantastic ideas. One article I really like is the HipsterPDA. Poking around his site, 43 Folders, I also found links to David Allen's website and found a plugin for Outlook that is supposed help quite a lot for those that get tons of email. I think I'll try it out.