If you purchased your iphone through ATT and still have them as your provider you are going to have this problem. Maybe not today but sometime in the near future.
Up until now we have been able jailbreak and unlock and run what we run - including SwirlyMMS.
Unfortunately for SwirlyMMS or any other Developer working on MMS projects, ATT has very recently decided to disable MMS services from every single data plan attached to or pointing at an iphone. They can do this accurately by indentifying your imei. Every single data plan that points to an imei that resides on an iphone is going to be affected.
I just got off the phone with a level 2 tech at ATT/Cingular and they confirmed this.
There are a couple ways that I know of to go around this:
1) Jailbreak, Unlock and use an alternate carrier.
2) Use a fake imei - you can learn how here:
http://www.hackint0sh.org/forum/f146/46 ... post349836Good luck.