Google Voice now lets you port your own phone number into its system -- as in, that 10-digit hometown relic you've been holding onto as long as you've carried a handset can now live in the cloud and grant you freedom to start afresh / forward to your many on-hand devices. Check under phone setting to see if "change / port" is now an option. The cost of porting is $20 and, as you may guess, it'll terminate your current service plan and probably prompt the carrier in question to charge applicable early termination fees, but that's pittance for saving your old line for the indefinite future. You know, just in case your seventh grade crush gets the nerve to call and say, "sorry." Of course he / she will, just give it time.
Update: Google just pinged us to note this feature is still being tested and may not be available to everyone. "We're continually testing new features to enhance the user experience. For a limited amount of time, we're making the Google Voice number porting process available to users. We don't have any additional details to share at this time, but plan to offer this feature to all users in the near future." We've seen it go in and out throughout the day, so yeah, just keep checking.