Facebook CEO Mark Zuckerberg officially announced Facebook Places feature. Places is a geolocation feature on Facebook that allows you to share your current geographic location or place with Facebook friends based on your GPS position.

Zuckerberg said that Facebook developed Places for the following three reasons:

1. Help you share where you are with your friends
2. See where your friends are
3. Discover new places

For now, Facebook Places is only available to users in the United States with mobile access (to Facebook app for iPhone or touch.facebook.com). Your mobile browser should support HTML 5 and geolocation feature. Apps for these & other devices are rolling out soon.

Go to Places on the iPhone application or touch.facebook.com site and then tap the “Check In” button. You’ll see a list of places near you. Choose the place that matches where you are. If it’s not on the list, search for it or add it. After checking in, your check-in will create a story in your friends’ News Feeds and show up in the Recent Activity section on the page for that place.

To get started, you’ll need the most recent version of the Facebook application for iPhone. You also can access Places from touch.facebook.com if your mobile browser supports HTML 5 and geolocation.