Google Voice has at last landed on the iPhone in full app form.  Long available with the Android platform, which currently outsells the iPhone in the U.S., Apple wasn't quite as kind to the Google product.

The service's ability to use a mobile carrier's data plan to send cheaper SMS texts and international phone calls irked both Apple and its carrier partners like AT&T.  An official Google Voice app was quickly removed from the app store.  Google responded by releasing a web app, with some of the original functionality.

Meanwhile numerous app versions floated around on the underground app store Cydia.  To run these versions, you needed a jailbroken phone, though.

Now two full Google Voice solutions have made their way to the official iTunes App Store.  Both are third-party products, using Google's API.  The two apps -- GV Mobile + and GV Connect -- have similar functionality, allowing users to access their Google voicemail box and use their iPhone phonebook, both to make and receive calls via their Google Voice number, and to send and receive texts using their Google Voice number.

Both have support landscape mode and the higher resolution iPhone 4's Retina Display.

Remember, if you frequently use the app it makes pretty heavy use of your data plan.  That could spell trouble given AT&T's low 2 GB/month data caps and high overage fees.