USE AT YOUR OWN RISK
1) This is experimental. The instructions might not work or might cause your phone to stop functioning completely.
2) at&t does not support this officially yet. There have been some reports of problems associated with enabling MMS on at&t.
3) The information is provided here for educational and informational purposes only. It should not be used on any phone.
This requires an iPhone 3G loaded with the iPhone OS 3.0 and 3.0 SDK installed onto a Mac with Leopard 10.5.
Step 1) Prepare the ATT_US.ipcc
Follow steps 1 - 7 from the instructions here.
1) Under Root in carrier.plist add:
AllowEDGEEditing Boolean Checked
AllowMMSCEditing Boolean Checked
AllowMMSEditing Boolean Checked
2) Add the following:
In the wap dictionary (mine is wap.cingular, sts's was wap.dol.ie), add a new pair. Do not edit the password or username:
type-mask = (NUMBER) -2
3) Under root in carrier.plist also add:
mms_proxy String 066.209.011.032
mms_proxy_port String 80
mmsc String http://mmsc.cingular.com
Now follow Steps 9 - 12 in the instructions to finish preparing the ATT_US.ipcc.