Official Google Voice For iPhone App Imminent?

Apple's publishing of their App Store guidelines for developers led to all manner of third-party Google Voice apps being submitted – and approved – for iOS devices, but now it seems Google's own app is set to imminently arrive.  TechCrunch has heard that the official Google Voice for iPhone app has already received its initial approval, and that it will pop up in the store as soon as the search giant has finished tweaking it to suit the Retina Display and iOS 4's multitasking.

How long that process will actually take remains to be seen, as does what exact functionality Google bake into their Google Voice app.  The Android version boasts significant integration with the underlying OS, including SMS support, but will have to work around Apple's limitations on the iOS version.  Still, push notifications for SMS and voicemail messages are likely to be included.