Googlevoice just twit on twitter "just launched the ability to change your google voice number. Your old number stays active for 90 days. Just got to settings > phone"
So now it looks like you can change your google voice number! Com'n google send me my freaking invite
hope this info helps someone
*Added from boygeniusreports*
Well it’s not incoming number portability but it’s better than
nothing… While the Google Voice team continues to battle through a
massive back log of customers itching for their invites, a nifty new
feature popped up today for current Google Voice users. Love the service
but hate your number? Well now you can change it on the Phones tab
under Settings . There is a one-time fee of $10 to change your number
but it’s a small price to pay. If you need help picking a new Google
Voice number, there’s even a great little number picker tool that lets
you type out words and try to snag their corresponding phone numbers.
The best part — your old number stays active for 90 days so you
don’t have to go crazy hitting all your contacts with your new contact
info in a rush. Sweet!