Apple Insider contacted Google, asking if they have any word on the official Google Voice app. The Google spokesperson replied:
We currently offer Google Voice mobile apps for Blackberry and Android, and we offer an HTML5 web app for the iPhone, a Google spokesperson said. We have nothing further to announce at this time.
In the past few days we have seen Apple approve Google Voice apps into the App Store and a change in their guidelines. It is true that we have a web app for it, but now that they can be approved, lets see what Google's next step will be.