Baseball-Reference

   If you like stats, you'll be in Heaven here

Baseball-Almanac

   The best general baseball information site on the internet, plus box scores for every game, every team, every year

MLB.com

   The Official Site of Major League Baseball

MiLB.com

   Minor League Baseball

The Baseball Cube

   Stats for every player who ever played

Baseball America

   "The Home for Baseball Insiders"

On Deck Baseball

   Prospects

Baseball-Statistics

   Hasn't been updated in a few years, but still some great stuff

Retrosheet

   All the unusual records

The Hardball Times

   Great articles

SABR.org

   The Official Site of the Society for American Baseball Research

Baseball Fever

   A fun site of baseball forums- history, stats, ballparks, current events and more

John Skilton's Baseball Links

   A big site of other sites