said by Asterix:U need to have a factory unlocked iPhone for Red Pocket.
Not sure why you chose Red Pocket when you could had gone with Straight Talk which uses AT&T network and you dont even need to unlock the iPhone as it uses AT&T network... plus it's cheaper than Red Pocket.
You do
NOT need it unlocked. A
locked att phone will work on redpocket, H2O, and straight talk since the SIM ICCID is the same (they use repainted att sim cards)