Here are some sites of interest
(sorry for moving these off the front page, but I have gotten a lot of requests and not much room to put them, so its only fair I just create a link and put some of them here)

Tennis Facts.com (Fredde's site)
Tennis Corner
The Grinders  (formerly PrizeMoneyTennis.com)
ZooTennis.com - Juniors Tennis
Tennis.info
TennisTeacher.com
RadioTennis.com
French Club Tennis
NCAA Men's Tennis Championships
TennisInsight.com
TennisAlternative.com