Is it possible to switch straight talk carriers?

I have an AT&T iPhone on straight talk. It was ok where I used to lie, but where I am now I have absolutely no service. Is there a way I can switch it to Verizon and get on Verizon towers, while staying on straight talk plan?

Yes, you would have to get a Verizon type Straight Talk phone (identified by the "CDMA-V" on the packaging) and transfer your services to it.