After a false start last week, Google Latitude is now available for the iPhone.  If you’re not familiar with it, Latitude is a location service along the lines of Foursquare and Facebook Places, and is available for most of the major mobile operating systems.

The main difference with Latitude is background updating, so all your friends can see your location in real time, rather than by single check-ins once you arrive somewhere.  It’s not exactly clear how the app shares this information, and only time will tell if your battery thanks you for having Latitude running in the background all the time.

The functions are as you would expect: share your location, see the locations of your friends and contact them via SMS, email or by calling.  It’s all customizable to ensure you keep your privacy should you want to, with the ability to control how precisely your location is shared, or to hide it entirely if you’re feeling secretive.

Google Latitude (iTunes link) is free to download, although it’s not available everywhere just yet.  We’ve seen it in the US and the UK store, but Google’s blog post on the subject suggests that over the next day or so, the app will spread to 45 countries with 15 languages supported.  You’ll need to own a 3GS, iPhone 4 or 2nd/3rd gen iPod Touch, all running iOS 4 or later, to use Latitude too.