Google recently announced that a number porting system will be added to their “Google Voice” service. Although currently still in a testing phase, this is sure to open up the service to new users.
Number porting allows a user to utilize their existing phone number (from another source) for their Google Voice account.
There are some caveats. Google may impose some steep early termination fees for current users when transferring over.
All things considered, this is a move in the right direction for Google Voice, as the world of telephone communication continues to integrate with the Internet.
[via TechCrunch]
Update
Google announced today ( 1/25/11 ) that they are offering number porting for all current Google Voice users.
http://googlevoiceblog.blogspot.com/2011/01/port-your-existing-mobile-number-to.html