WoW, looking through all the messages on hofo, I didn't realize that you can activate a LOCKED att iPhone with airvoice.
I have been waiting for att to get my unlock code from apple (now a 11 business days and counting) so hopefully as soon as I get it I will be able to use my features my iPhone 4 has with Airvoice.
Anyways, I had to call Airvoice, after I screwed up getting a pin for my new activation on my iPhone, and have to say that there customer service is FIVE STARS!!
It is a long standing fact that most Att mvno sims (Jolt, Red Pocket, Air Voice , H20, Skyview, Fuzion Mobile, Horizon Mobile, Pure Talk/Prepaid, others) will work in a locked Att phone (new Att type/post Cingular era).
Iphones will generally work too without unlocking. MMS MAY require jailbreaking. (Correct me if this info has been updated).
Some mvnos are more conservative then others. Red Pocket for one will not guarantee it except for unlocked phones.
I know talk/text work for sure with most locked Att phones with Att mvno sims. Data/mms. May vary.
And of all the Air Voice mvnos, Air Voice has the consistently best CS and one of the fastest too. Plus US based. Their con is that they have shorter hours then other mvnos...