After the dustup between AT&T, Apple, and Google over the rejection of an official Google Voice app for the iPhone, there was little reason to hope that such an app would ever appear on the iPhone. Even an investigation by the FCC didn't change Apple's position, and it even led them to remove all the unofficial Google Voice apps from the app store. So what did an undeterred Google do? They wrote a web app.
Ironically, before Apple created an SDK an officially allowed applications to run on their iPhone and iPod, they tried to convince developers that the way to get their content on the iPhone was through the web browser. Needless to say, back in 2007 that idea flew about as high as a lead balloon, but Google returned to that approach to create their Google Voice client for the iPhone. As a result, there was no submission needed and nothing for Apple or AT&T to reject.
The "app" in this case is accessed by directing the Safari mobile web browser to the appropriate web site. At this point, Google's HTML 5 code takes over and presents a screen that is virtually indistinguishable from an app running natively on the system. It is intuitive and responsive, and save for the Safari toolbar at the bottom, it occupies the whole screen. If you pull down on the screen, you will see the browser URL bar at the top, but other than that, the illusion is nigh flawless.
Google Voice has all the features you've come to know and love with sections for your Inbox, your contact list, your text messages, and your calls. Interestingly, the calls are handled differently from the way they are when using GV on a computer. Instead of having GV ring a designated phone number and then connect you to the party you requested, you will receive a prompt asking for permission to have your phone dial a Google designated number. Say yes, and your phone will dial and from there you will be connected to the requested party. Some people have complained about having Google's numbers appearing in their call log or on their phone bills, but it isn't a problem from my perspective. In fact, some people may even appreciate the added privacy.
Google's solution to this problem works so well that it begs the question of whether Apple wasn't right to suggest that web apps were the way to go. And for those companies who have had apps rejected, is HTML 5 the solution? I suspect that while there may be some apps that could find improved life as web apps, that approach presents its own hurdles. First, it requires the expertise to write such an app using web techniques. After an investment in learning Objective-C, this might be prohibitive. Then it needs to be hosted somewhere, meaning bandwidth will be a cost. Finally, it will probably be harder to monetize. Sure you can present advertisements, but you probably won't be able to collect an up-front payment as easily as selling through the App Store. These obstacles might be easy enough for a behemoth like Google to overcome, but they could be prohibitive for a smaller developer. And I doubt that apps like games would translate very well to a web format, but a proficient coder could prove me wrong there.
In the meantime, I have not only bookmarked the Google Voice web page, but I have added an icon for the bookmark to my home screen. So now not only does the web app feel like a native app, but it gets executed like one too. I can't recommend this one highly enough.