Google Inc. (NASDAQ:GOOG) has announced that you can now port your existing mobile number to Google Voice. To set it up, log in to your Google Voice account and click the Settings page. From there click on the Change/Port option next to the Google Voice number. Porting your phone number to Google Voice costs $20 and can be completed within 24 hours. However you may incur early termination charges based on what your current wireless carrier charges. You may want to double-check whether your contract terms have expired or not. After your phone number is ported over, then your mobile service plan will be canceled. You can see a video demo of the service above.