Recently, there have been public tussles between companies I used to work for. Apple has blocked Google's Latitude and Voice products from being in the iPhone App Store, for reasons they haven't disclosed, though it is speculated because they compete with built-in applications or carrier plans.
The iPhone App Store has gathered so much buzz recently, that it has obscured the underlying effect of the change that is happening due to the iPhone and its imitators. An iPhone is not so much a phone, as a good Web browser in your pocket that works everywhere. By incorporating the excellent Webkit browser, iPhone tipped the pocket net experience from email-like to fully web-like. As I said at its launch, even Steve Jobs can't ignore the Web.
As iPhones, iPods, Androids, Palm Pre Chrome, Safari and some Nokia phones now run Webkit browsers, the growing part of the Web browser usage is in a browser that supports HTML5 and the geolocation, video, vector graphics and local storage APIs that that implies. So Google Voice's website UI can work on iPhone, Android et al and make calls, as can other web applications that make calls.
The real platform that everyone can build on is still the web, and attempts to enclose or limit it will continue to fail. The Open Web Foundation, which I'm proud to be a member of, is working to keep this true and make it easier to grow new web standards and agreements.