Foursquare is probably quaking in its boots right now as Facebook Places has finally launched in the UK.

Introduced in the US last month and Japan earlier this week, Facebook Places will be rolled out starting this morning (Friday) and should be available for everyone in the UK within a couple of days, either through the Facebook for iPhone app or through the mobile site,

The new service lets you check in and share where you are in real time so that your friends can find new places that you've discovered and vice versa. It's also great for avoiding situations where you've been to a gig or a pub only to find out afterwards that your pals were there too. (Of course they may have known you were there all along and just done their best to avoid you).

If the usual scare stories about having your house burgled by web-savvy thieves have got you worried, Facebook is offering assurance that Places is an opt-in service so you can only ever be chekced into a location if you've authorised it. The social networking giant says that Places doesn't store a record of the user's location, unless you enable it to by checking in or accepting a tag from a friend. You can also control which people can see where you've checked in - supposedly the default will be 'friends only'. You can also turn off the 'Here Now' function so that you won't turn up on a location's Facebook page unless you want to.

There are various other bits of common sense built into the privacy settings, for example, you’ll never be able to tag someone who’s not a friend, and no one who you’ve blocked will ever be able to tag you. There's also an extra level of protection for the kids - their names will only ever show up to their friends on the 'Here Now' section, and only their friends will be able to see if they check in.

It all sounds like wonderful fun until someone gets caught somewhere they shouldn't be. Use with caution.

Have you signed up yet? Let us know what you think.