Aurora Feint creators Danielle Cassley and Jason Citron (pictured) have announced that they're working on a new game that will use iPhone 3.0 features like push notification and microtransactions.

It's said to be nothing like their previous RPGs, so we're thinking something more colourful and casual, but the pair weren't giving much away at WWDC last week.

Due for release later this year, the game will, however, use the OpenFeint connected iPhone games platform, which has just launched its v2.1 beta incorporating these features.

"Danielle and I are personally planning on publishing a brand new game this summer using these features in innovative ways that will push the frontier of game development on the iPhone just as we did one year ago with Aurora Feint: The Beginning," says Citron.

The latest version of OpenFeint will let developers put challenge features in their iPhone games, using push notification to let players know when someone wants to battle them.

In-app payments will also be tied in, and the company has outlined an example of how this will work:

"Danielle sends Jason a challenge using content purchased with Microtransactions. Jason clicks through the Push Notification and is prompted to purchase the content Danielle selected so he can play her challenge. With one click of a button, he purchases the content and jumps right into the game."

Sounds good to us: we'll keep you posted on the new game as we get details.