If you've just bought a Mac or upgraded iLife, and are ready to master the new features in iPhoto '11, then I think you'll enjoy iPhoto '11 Essential Training on Lynda.com. Here's a short introduction.
There's more than four hours of training presented in a series of short movies that you can watch as many times as you want until you feel comfortable with each particular technique. It's truly learning at your own pace. Even if you've never used Lynda.com before, there are three free movies that you can view right now: Working in Full Screen Mode, Hiding Photos, and Creating Smart Albums.
I receive lots of mail about how much people like learning software via my titles on Lynda.com. If you're ready to dig into iPhoto, or want to give a loved one the gift of knowledge, then take a look at iPhoto '11 Essential Training.