Facebook's new Places feature lets you share your current location by "checking in" from your smartphone. Whether you never really got into earlier location-based social networking services like Gowalla or Foursquare or just want to know what it is (and how to turn it off), read on for everything you need to know about Facebook Places.

Keep in mind that Places isn't available everywhere just yet--early reports indicate that it's United States-only, for now, but with significant gaps at the moment - so you may just have to wait.

Checking In Via Smartphone or PC

Before you can share your location with your Facebook friends, Facebook needs to know where you are. Just open touch.facebook.com in your web browser (or use the Facebook for iPhone app on your iPhone, iPod Touch, or iPad), and you'll see a tab under "Inbox" called "Places." For the iOS app, it'll show a new icon in the middle of the home screen.

Tap Places, and you'll see your recent check-ins as well as your friends' check-ins. From here, you can find out more details about the places your friends are checking into (map location, description, directions, comments, and other check-ins), or you can check yourself into a nearby location by pressing the Check In button at the top-right corner of the page.

If you can't find the right place to check in from, you can browse more nearby locations by pressing the right arrow button under the Places tab until you find it (if you're using the iPhone app, just scroll all the way down and press Show More Nearby Locations).

The list of available locations comes from other people's check-ins and listings from Bing's mapping engine, so you might have to add your location yourself--just press Add, and it will take you to a page where you can fill out a name and description.

Once you tap Check In, you'll be presented with a list of nearby locations where other people have checked in. Tap the one you want to check into, and you can choose to comment on what you're doing there or add your Facebook friends to your check-in (Press the What are you doing? and Tag Friends With You buttons, respectively). Next, press the big Check In button, and it will show up on your News Feed.

While Places is mostly meant for smartphone users, it doesn't depend on a GPS device to find your location--you can check in from a laptop or iPod Touch, too. Just go to touch.facebook.com in your browser (you'll need Internet access, of course), and you can check in from your desk or café.

Checking In With Friends

Unless you're on Facebook just to show everyone what a loner you are, you'll eventually want to add the friends you're hanging out with to your Facebook Places check-in. All you have to do is choose the Tag Friends With You option while checking in.

Once you've added your friends and checked in, it'll show up on their News Feed as well. If they haven't used Facebook Places yet, it won't show up on their feed until they've approved the check-in; they'll see a little alert the next time they log in, asking them to allow or deny the check-in.