How can I use my iPhone 2g?

I have a pantech at&t phone right now, but my friend gave me his old 2g.

When I put my sim into the iPhone, it just shows a cable and itunes, saying plug it into itunes. I can't get out of this screen even if I take out the sim, and I don't want to make it work through itunes because I don't want a data plan.

I was wondering if there was anyway to jailbreak it with it currently locked and not able to get out of that screen (the sim doesn't have a pin on it by the way) and be able to use the plan that I have on it right now, unlimted texting, 1400 minutes per month, but still have the data plan blocked?

I've been looking all around and I can't find anything that works for my situation.

Any help is very appreciated, I'm not a computer wiz at all and this is really bugging me! Thanks so much!