Eric Gunnerson writes about a very useful-sounding book in this post on his blog. Take Back Your Life - Using Microsoft Outlook to Get Organized and Stay Organized looks like a pretty good resource for organizing tasks and work habits.
It looks like folks with huge e-mail inboxes should benefit from some strategies put forth in the book -- a goal in the book is to have zero items in one's inbox. You read an e-mail and either delete it, delegate it, move it to a task or file it elsewhere for future reference. What a concept.
I've got the book on order through the library and look forward to reading it. My e-mail inbox is tiny these days, but I may get some good tips on efficiently handling mail when I do get back into the workforce.