As the 2010 World Cup kicks off in South Africa today, millions of fans across the globe will be tuning in and logging on to root for their favorite teams. From Facebook games to exclusive Foursquare badges, here are four sites that get you in the game and off the sidelines. 1. Live StreamingESPN3.com is streaming 54 World Cup matches for free. Head to their website and click "Watch Now" for the current match, where you can also view up-to-date stats.Univision will also be streaming matches online for free (but this site is in Spanish). To watch, click "Ver partido en vivo" from the orange box in the top right corner. 2. TwitterFollow the official account, @2010OC, for live news updates, TwitPics from the scene and the inside scoop on the happenings in Johannesburg, South Africa.Also, check out Twitter's World Cup page where you can view a stream of live World Cup tweets from around the world and even sort them by match. Or, check out Twitter's Staff Picks for the World Cup for new accounts to follow (including some popular soccer stars) and the latest information.And don't forget to mark your World Cup tweets with the hashtag #WC2010. Search for this hashtag on Twitter to find out what others are saying, too.3. FacebookFacebook has a number of ways you can enjoy the World Cup. Check out the Goal Leaderboard, a contest that Facebook is holding to see which country has the most passionate fans. Click "Support" and encourage others to do the same, and watch your country climb the ranks. Or, take part in EA Sports FIFA Superstars Facebook game where you can build your dream team and challenge your friends to online matches. 4. Foursquare. Foursquare has partnered with CNN to release two new badges: the South Africa Explorer (which you can unlock only by venturing to South Africa to attend the World Cup) and the Superfan badge, which is earned by checking in to World Cup viewing parties and soccer-friendly pubs. Staff Writer Kristin Burnham covers consumer Web and social technologies for CIO.com. She writes frequently on Twitter, Facebook, LinkedIn and Google. You can follow her on Twitter: @kmburnham.