Hi, I'll be on the US for a month and was planning on buying a prepaid ATT sim card to use on my factory unlocked iphone 4 for voice/data. In the ATT gophone website they say you can buy a data plan to use on your smartphone, so I though it'd be ok, but several sources say that data won't work on iphones. People say that as a workaround you can activate data on a different smartphone and then insert the simcard in the iphone, but I also read ATT can block data if they detect that it is an iphone IMEI. Has anyone ever tried this? Will they really block data? Thanks!