Foursquare has upgraded its Android and iPhone apps to version 3.0 to kick off some new and enhanced features.

Officially debuting yesterday in Apple's App Store and Google's Android Market, the free Foursquare 3.0 app has added a new Explore tab that can zero in on the places you want to go.

Tap a certain category, such as food, nightlife, or shops, or type in a specific phrase, such as "books" or "gas station," and Foursquare will show you a list of local spots, anywhere from 2 to 10 miles from your current location. For each spot, you can read recommendations and comments from your friends and other users, helping you decide whether to check it out or steer clear.

Foursquare has also revamped the Leaderboard, which now displays the number of points you've picked up over the past week along with the amount of check-ins, badges, and possibly mayorships you've earned by finding new places, adding friends, and taking care of other tasks.

Finally, the 3.0 upgrade has enhanced the Specials feature, which alerts you to sales, discounts, and other promotions from nearby stores and businesses. Foursquare has added six new ways for local shopkeepers to reward your loyalty, helping you on the road to becoming mayor. You can also now more easily see all of the nearby specials by taping the Places tab.

More details on the latest upgrade can be found in Foursquare's recent blog post. The iOS app is compatible with the iPhone, iPod Touch, and iPad and requires iOS 4.0 or higher. The Android edition requires Android 1.6 or higher.