Sorry if this has been discussed. I was wondering about using the new iPhone 3G on my old 2G plan, do you think ATT will know and make me pay more? I'm currently paying about $75 a month (with taxes and all the fees). For this, I get 450 mins + 5000 nights&wknds and unlimited data + 200 sms + unlimited mobile to mobile sms. I think it's really a good deal since all my friends that I text with are on ATT (and I text more than 2000 txt's a month). I suspect that I wouldn't be able to get the $5 unlimited mobile to mobile sms on the 3G plan, so I would have to go with the $20 unlimited sms. That would put me at 69.99 + 20 = $89.99 + taxes and all the fees which would put me at about $105 a month! That's almost $30 extra per month ($360 per year!! or $720 for the 2 years period!!!!!!). So I'm thinking maybe if I can just get the $699 16GB iPhone 3G (and somehow unlock it) and use the old 2G plan. Do you think I will be able to?