Facebook places has just been released to be used on an a smartphone. If you don’t have an iPhone , you’ll have to use the Facebook touch mobile site on a browser that supports both HTML 5 and geolocation.
To use Places, go to the Places tab on the iPhone application or touch.facebook.com. You’ll first be asked if Facebook is allowed to know your location. Once you click “allow,” you’ll enter the Places interface. From there, you can share your location with friends, find out where your friends are (if they’re using Places), and discover new places near you.
You can add places, check in to places that already exist, and tag people who are with you. If you’re checking in for a group, make sure you tag your friends before you checkin, yourself. For example, I added my house and checked in there. I then opened the Places page for a nearby sushi restaurant, tagged my boyfriend, and checked us both in there. Learn more
There are other applications that allow you to track friends and places.
Gowalla – Connect with friends from Facebook and Twitter to share where you’re going. Take a Quick Tour to learn more
Grindr - Meet guys at home or on the road for free with Grindr for iPhone or iPod touch. Heterosexual application coming soon!