As far as I know AT&T is still locking the pay as you go plan to certain phones, meaning it will not work, but I have not tried it myself.
i have been given an iphone (niece upgraded! to 3G)
can i sign up for a month to month AT&T account, get a cheap AT&T phone
take out the sim card and put it in the iphone and expect it to work?
thereby not paying additional charges and not entering into a lengthy contract. Thanks iroscoe