Hey all -- I'm looking to sell my out-of-contract AT&T iPhone 4 16 GB sometime this week, and just use my SIM card in a cheapo temporary phone in the meantime (with a micro-SIM adapter). Has anyone run into problems doing something like this? I.e., would AT&T see that the iPhone 4 is no longer on the account, and give me grief when I'm trying to upgrade? I don't plan on making any rate plan or account changes during this time, was just curious what other folks may have run into. Thanks!