Google's Voice HTML5 web app for iPhone now supports iPod Touch and iPad. A new version of Google Voice can now be downloaded, which gives users all the features of the iPhone app on iPad and iPod Touch, such as sending and receiving free text messages — except make cellular calls.
According to the Official Google Mobile Blog, "While you can’t use your iPod or iPad as a phone, you can use it to initiate Google Voice calls with your phones. We call this feature Click2Call. Simply click any 'Call' button in the Google Voice app on your iPod or iPad and then select which of your phones you want to ring. Google Voice will call your phone and then connect your call."
The Google Voice app works on iPhone, iPad, or iPod Touch with iOS 3.1 or later and a valid Google Voice account, and currently is available only in the U.S.