If you are currently a Sprint customer, you can now opt in to make that Sprint phone number your Google Voice phone number. This isn’t number porting, Sprint retains control of your number. They simply tell Google when you make or receive calls, and forward that call to other phones if you’ve chosen those options. Google also takes over the voicemail for the phone, and long distance calls are completed by Google at Google’s very low international rates.
A major carrier actually letting you use all Google Voice's features while retaining your existing number (i.e., not needing to port)? Wow.