Google Voice opens up existing number

[gianthobbit]

For those of you who have not read this yet: http://googlevoiceblog.blogspot.com/...ng-number.html

This is awesome but before I do anything just want to make sure this is compatable with Sprint. I know a while back when I wanted to get visual voicemail that sprint would charge you for forwarding the calls. Anyone know if this is the same deal?