gophone iPhone on AT&T GoPhone

[Shadrack]

So I received a carrier unlock for my iPhone 3GS from AT&T and I'm thrilled. Just tried out putting $15 on a pay-as-you-go GoPhone SIM, stuck it in and everything worked great.

I currently use my iPhone 4 and it is on contract for a little more than 2 months. I'm considering switching my phone number over to GoPhone, putting $100 worth of minutes on it (they don't expire for a year) and just paying $25/mo for 1000 txts and 200MB.

I have verified that voice and txts work but I see that there is some sort of "hack" (non-JB) to get 3G data to work over the GoPhone network.

I would be thrilled if I was able to use this because simply put I don't use voice minutes and am tired of paying $75/mo for my cell phone. I'm worried that AT&T might take actions to prevent iPhones on their GoPhone network, though...