I'm trying to use my iPhone 3GS SIM card with my original iPhone 2G but, when I put the card into the 2G, my phone acts as if it has never been used. I'm given the "USB cable and iTunes" screen on the phone, and iTunes tries to take me through the activation process. This is all fine and dandy, but I don't really know what to do when it gets to the point where I have to reselect a data plan. I'm given only one data plan option, $20 per month, which is not the $30/month unlimited 3G plan to which I'm accustomed. I also am told to select a text message plan, which leads me to believe that I might possibly be charged twice, as if this is an alternate line. Is this process normal, or has everyone else who switched from their 3G/3GS to an older phone in anticipation for the iPhone 4 encountered a more seamless transition?