US location-based social networking company Foursquare has raised $1.35 million in its first round of funding, according to TechCrunch.

Companies involved included Union Square Ventures and O'Reilly AlphaTech Ventures, plus some angel investors.

Currently focused on 20 US cities, and Amsterdam, Foursquare is available for iPhone, iPod touch and Android, with BlackBerry and Windows Mobile apps due soon.

Using GPS and/or cell/wi-fi location, the free app lets you tell your friends where you are - "checking-in" - and links into the real-world by enabling you to unlock rewards such as special offers at bars and shops as you go to those locations.

In addition, the app can alert you when you're near a location where rewards can be found; something that's combined with the idea of Mayors - or the person who has the most check-ins in that particular location.

What's also neat is that you have to actively trigger the sending of your position, meaning there's less issue with privacy concerns.

You can sign up to Foursquare at its website, or get the app at the App Store [Link] or Android Market.

[source: TechCrunch]