All, I currently have a grandfathered voice plan (North America 800) with a blackberry data plan. I have access to an activated Iphone 3g. If I can get a 3g sim card from att (tell them I bought a 3g phone in Europe) would it be possible to use that 3g sim card in an activated Iphone 3g? I understand that ATT scans to see if the data plans are correct. Following, if ATT saw i was using a Iphone 3g on an old voice plan and incorrect data plan, would they switch the data plan, but leave the voice plan intact? Frankly, I'm only interested in keeping my grandfathered voice plan...what att does with my data i couldn't care less. Thoughts? Experiences? Thanks!