Despite recent drama, Google Voice will soon be available for iPhone -- as a Web-based app, says The New York Times.

It is unclear if Apple would reject a repurposed Google Voice app. But earlier in the year Apple did allow Google to promote Latitude as a Web app after it was rejected from the App Store.
Considering their recent decision has managed to draw attention from a wide range of people, including some at the FCC, it probably wouldn't be the best choice to block a rethought Google Voice app.
Google Voice Can Sneak onto iPhone - PC World