Sabermetric wiki
Tango Tiger has created a wiki page for all things sabermetrics. If you know what you’re doing, go make some pages … that’s the point of the wiki setup, I believe. If not, bookmark the site and go back often when you have a question about something. It could certainly become an invaluable resouce, and it has the advantage of having everything all on one page (on a specific subject), rather than just a bunch of various links as I’ve tried to compile here.