I've collected some links for those of you seeking a better understanding of sabermetrics.
Sabermetrics 101: from the blog Lookout Landing (Seattle Mariners). There are 10 different posts, covering a variety of topics.
Metaprimer: wOBA: from South Side Sox (Chicago). The main thrust is wOBA, but it gives some background so you can see how it's put together.
Guide to Stats: from River Ave. Blues (Yankees). An accessible, readable summary, making it a good place to start.
FanGraphs Glossary: The stats used on the FanGraphs site are explained, but scroll to the end of the page for two seven-part series by Dave Cameron on Win Values. Good stuff!
The Hardball Times Glossary: A very handy list--with links--of the acronyms and abbreviations the stat-heads throw around.
Everything you always wanted to know about (the new statistics): Alex Remington's collected articles for Big League Stew (on Yahoo Sports) covers stuff like BABIP, WAR, UZR, etc.
It's okay to be mystified by linear weights: An excellent THT article by Joshua Fisher that pounds home the point that I make below, namely, that you need to grasp the ideas rather than the math.
The FJM Glossary: Mr. Fisher's article above links to the now-defunct Fire Joe Morgan website for this priceless glossary. Just in case you thought saber-folks had no sense of humor.
The Monster in the Mirror: JT Jordan at THT explains linear weights.
The Sabermetrics Library: The ultimate source--some of the materials above are included at this site.
That's enough to keep the nerdiest of you busy for a while. Try not to absorb the stuff all at once--just get a feel for the general assumptions behind the metrics, and how they require you to look at the game a little differently than you used to. The best part about sabermetrics is that there are plenty of math whizzes out there to do the work. We have the luxury of enjoying the fruits of their labors! As you begin to grasp the new stats, you'll find that the old ones you grew up with are less and less revealing. You'll start asking more questions about context, and you'll seek new kinds of comparisons. Baseball is great--we've spent our lives being "students of the game." The more we learn, though, the more we realize how little we know. That means we get to be "students of the game" forever!