Here are a few of my favorite pool websites.

A great website for all aspects of pool. Excellent forums.
http://www.azbilliards.com/

American Cue Sports.
http://www.americancuesports.org/

Player ability test information.
http://www.pat-billiard.com

A excellent site to get professional player videos.
http://www.accu-stats.com/

A good general resource for books and videos
http://www.bebobpublishing.com/