Just wondering if it would work without the 3G service obviously... I plan on getting a 3G iphone without getting the contract and just using the remainder of my 2G iphone contract.

As far as I know, it won't. I could be wrong though.

yes it will work but i dont think you can get away with it long i think att on the back end can tell if you are using 3g service i think i maybe wrong but i know for sure a 2g sim inserted into a 3g phone works fine and i was surfing with 3g speeds