Ok, never mind I was about 6 months ahead of myself thought it was out of beta and they took all my invites sorry. It is free
Anyway when it comes out of beta
1. sign up for google voice.
2. Put your Google voice number in your top 5 or whatever you call for free.
3. First the incoming to your Google voice account will always be forwarded to the cell hence free.
4. Second dial out by calling your Google voice account and dialing out through there from your cell phone. Hence you are calling Google voice so that is free.
On a side note for every call you make through Google voice you get credits for international calls. So those will also eventually be free depending on how much you use it.
If this does not make sense I'll explain further. My brain is fried today.
