RobNeyer.com 
The official site of ESPN baseball journalist Rob Neyer. Features regular columns from Rob and others. Heavy focus is on the Kansas City Royals, of which Neyer is a die-hard fan. He's also written a book called "Baseball Dynasties" and does radio appearances on ESPN Radio.
http://www.robneyer.com/The Diamond Angle Baseball Magazine
The Diamond Angle is a small baseball magazine published out of Hawaii. Features include interviews, photo albums, past player profiles, and book reviews.
http://www.thediamondangle.com/
Baseball Think Factory
A collection of essays on baseball's economics and sabermetrics, along with the Baseball Newstand, and a collection of links to baseball media and columnists.
http://www.baseballthinkfactory.org/
Baseball Blogs
Features many weblogs devoted to individual teams, multiple teams, or the sport as a whole.
http://baseballblogs.org/
Blogging Baseball
All-time baseball highlights and real-time commentary.
http://www.blogging-baseball.com/
