Here are some sites that are worth checking out… in no particular order
WTA Tour – the home of women’s professional tennis, including live match updates and a wealth of data about the top players.
ATP Tour – the home of men’s professional tennis, with all the information on matches, players and tournaments.
International Tennis Federation – the international governing body of tennis, including all the tour calendars.
United States Tennis Association – the governing body for the USA. A great resource for players, including amateur rankings and local tournaments.
International Tennis Hall of Fame – dedicated to the history of tennis and celebrating its champions.
US Open – official site of the US Open Tennis Championships. A great starting point for anybody wanting to attend the tournament – including ticketing.
Tennis on Wikipedia – if you really want to become an expert on the game, this is a great starting point. Who knew that a catalyst for the creation of the modern game was the British invention of the lawn mower?