The OS X list . Once you've signed up (at www.themacintoshguy.com/lists/X.html), your email In box will overflow with Mac OS X discussion, chatter, and discoveries. A great place to ask questions, both simple and difficult.
TidBITS.com . A free, weekly Mac newsletter with lots of useful tricks, reviews, and news.
Apple's own newsletters . At www.apple.com/enews/subscribe, you can sign up for free weekly newsletters on a variety of topics: music, QuickTime, programming, and so on.