Hot on the heels of Gmail's largely underwhelming release of its iOS app, the Sparrow crew confirmed today on Twitter that an iPhone app is definitely in the works. While we've seen hints that Sparrow was working on an iOS app for some time now, the team threw a zinger Gmail's way by announcing the "Gmail experience you deserve on your iPhone" will be coming in a few months. The desktop Mac OS X Sparrow mail app has built a steady following as an alternative to Apple's default with Facebook integration, full Gmail label support, Growl notifications, and a unified inbox.