ATP Tour Official Site - This site is availble in English or German. It has all the news you need on what's going on every day on the ATP tour. Perhaps the site's best feature is its search engine for current and former pros. They also have a trivia tournament and virtual tennis game, but the latter requires some serious downloading if you've got the time. They have links to tournaments in the area and a membership form.
Site seems to have some link problems from time to time.
Francais is a nice and very complete site. They have detailed information on Canadian tennis players of all abilities including professionals and wheelchair players. There are links to the professional tours and Canadian tennis' premier events, the du Maurier open for women, and the Canadian Men's championship. This group has lots of tennis activities for those living in the Dallas and Ft. They have events for corporate tennis matches, a list of area tennis players and locations to play.