Currently available by invitation only, Google Voice is already offered as a mobile app for Android and BlackBerry handsets. The service ties together multiple landline and mobile phones under a single number and includes some features that compete with services AT&T charges for. Chief among them are free SMS messages and cheap long distance calls as well as advanced call screening features – you can see where the conflict of interest lies. Many are blaming AT&T for the rejection, but the companies have yet to clarify this issue.
In the meantime, iPhone users can still access many of Google Voice’s features by using the web interface. It won't work as seamlessly but it’s something. The question remains, though, should Apple get to decide what applications your iPhone can run?