Here are some good tennis blogs out there. If you know of any others that should be added to this list, just e-mail me at email@example.com.
Shahar Peer's Coaches Blog: Blog of Pablo Giacopelli.
Racquet Network: A networking site for all kinds of racquet sports.
All Tennis Considered: Excellent Blog by Tyler Smith.
On the Baseline: Women's professional tennis news.
On Tennis: Collects tennis news.
Racquet Master: "Taking Stock of Tennis and Squash"
Andy Roddick: Roddick Watch.
Sexy Maria Sharapova: Don't worry, it's not what it sounds like. Just a very nicely updated Maria Sharapova blog. And yes, it does have a lot of photos.
Tennis Buzz: Only in French, but since I haven't found that many regularly-updated tennis blogs yet I'm adding it to the list. A very nice blog.
Tennis Musings: "A place for tennis discussion and basic tennis journalism"
Tennis World: Peter Bodo's entertaining blog over at the Tennis Magazine website. You won't always agree with him but he doesn't lack for opinions or insider access.
Zoo Tennis: An excellent blog covering junior tennis.