Apple promises that its upcoming iPhone 3.1 release will be the first to officially support augmented reality apps that support the iPhone 3GS’ camera.

iPhone developers and users excited by the prospect of augmented reality apps, which overlay information and controls on top of real-world objects seen through a camera, have been told to sit tight until the next release of the iPhone OS exits beta.

Although iPhone 3.1 has so far only been known to expose some video camera controls for developers, third-party producer Acrossair was told by Apple that the future release would be needed for its Nearest Tube and future Nearest Subway apps to work properly.

The apps are already highly dependent on the built-in compass and autofocusing camera of the iPhone 3GS, both of which are needed to alternately recognize the direction the iPhone is facing as well as to get a detailed enough look at a subject to tag it with information.

Unofficially, iPhone 3.1 is anticipated to be ready by early September, just in time for Apple’s by now yearly iPod updates and the seemingly probable release of an iPod touch with a camera that could take advantage of augmented reality when using Wi-Fi.