Here's a useful corner of Apple's enormous website. The "Find Out How" pages feature tutorials on things like Mac and wireless basics as well as web, music and MobileMe tips.
We've written about it before, but Apple has recently added tutorials for iLife '09 apps, including iPhoto and an iLife '09 overview. The tips are super handy, and even an old salt like me learned something new. For example, did you know you could publish to FTP with iWeb? I didn't (of course, I never use iWeb).
Of course, you can check out our own Mac 101 series as well. Here's to education!