Facebook has developed an application similar to Foursquare called “Facebook Places”.
In case you aren’t aware, Foursquare is a geo-location application, or as Business Insider more eloquently puts it:
“Foursquare is primarily for letting your friends know where you are and figuring out where they are. Secondarily, it's for collecting points, prize "badges," and eventually, coupons, for going about your everyday business.”
Facebook’s Places doesn’t bring forth the prize/badge aspect of Foursquare, but it does alert your Facebook network as to where you’re at, at your discrection, quite similarly to Foursquare. If you have Facebook on your mobile device, check out touch.facebook.com to set yourself up or learn more about the application by reading the Facebook Blog Post.