If you're a fan of innovative free iPhone games, you need to get over to the App Store now to download a copy of Booyah Society.

It's just gone live today, and claims to be the first iPhone social game based on your real-life achievements. Which means you get rewarded for your posts and activities, and for interacting with friends.

Everything's tied in with existing social networks Facebook and Twitter, and as you progress, you unlock an increasingly customisable 3D avatar.

If that sounds a bit strange, well, it is. But it's one of the most intriguing efforts we've seen to wrap a game-like structure around social networking on iPhone (Foursquare would be the other example).

What's more, the startup behind it, Booyah, was set up by three former Blizzard Entertainment staff earlier this year, who raised $4.5 million of funding to pursue their iPhone dream.

Having worked on games like Diablo III and World of Warcraft, their first iPhone app is certainly worth checking out.