If you have both a Google Voice number and a Gizmo5 number you can use Sipdroid, for now, http://sipdroid.org/ to receive and make calls. You need to set the Gizmo number as one of your phones in Google Voice settings. When you receive a call or initiate a call(easily accomplished on the web page in desktop mode) from your Google Voice number the edge will ring if Sipdroid is on and connected over wifi. Unfortunately, in April Gizmo will stop providing service, Google bought it quite a while ago. They are promoting their service through chat - and offer call phones for free in the US until the end of 2011. However, this function needs flash; which we don't have yet.