OK i had swirly working and the restored my phone and it stopped working. After a few days of trying this is what got it working again.
1.) Install Swirly (DUH)
2.) Put your sim Card in another phone. Use the phone for a bit.
3.) Log in to your att account and see if you have the option for Unlimited Messaging. Not the iphone one the regular one. If your on the iphone plan switch the option should be there if you swapped ur sim and the system has recognized the other phone. If not us the phone some more.
***This is where i had trouble because I already had the Unlimited messaging and it still wasn't working. What i did was switch back to the iphone plan put the sim back in my iphone and used it for a bit to register it on the network. Obviously swirly didn't work. I then repeated steps 2 and 3 and changed back to messaging unlimited. After that it started to work again.***
4.) put your sim back in your iphone and try any of the settings should work but i use the one with all the blanks filled in.
If this dosnt work i have also hear about enabling wap push. I didn't call to do this because i use mobile me so this is already enabled on my account. If you don't want to bother with att just get a free trial of mobile me.
Also if it dosent work download the apn configurator from cydia and change the settings to
apn: wap.cingular
user: [email protected]
pass: CINGULAR1
This is what i did it may or may not work for you but it is another option to try.