Is there any way I can use an AT&T iPhone 4 on the Verizon network?

My friend just got the new iPhone 5 and my old phone broke so he gave me his old iPhone 4. The problem is he has the iPhone 4 from AT&T and my plan is with Verizon. I've heard its possible to unlock the phone free by calling AT&T since his 2 year contract is up with that phone, so that it can be used by any carrier. However I know AT&T uses sim cards and Verizon doesn't.

Is there ANY way I can use this phone with Verizon? I have no other options for a new phone.

Jailbraking does not fix this problem. You need a factory unlock. Email me at stefan_zxcvb@live.com and i will explain everything