One of people's biggest complaints about the iPhone last time around was the lack of flexibility when it came to SIM card use. You simply could not switch out the SIM card--even to a different AT&T one!  [caption id="attachment_3106" align="alignright" width="150" caption="Prepaid GoPhone on the iPhone 3"][/caption] But now with the iPhone OS 2.0 update, you can use all of those AT&T ... continued »