UNLOCKED IPHONE!!!!!!

Hi I have a 4GB iphone, which i accidentally upgraded to 2.0 version and then I had to delete and reinstall itunes and the 1.1.4 version for my Iphone because it wouldn't work! I used ziphone to jailbreak and activate my phone. It said it would unlock it as well but IT HASNT! I can open the phone, use the internet, but i just can't make phone calls! I tried taking the sim-card out and puting it back in but it just wont work! I have prepaid ATT so I need it to be unlocked for any GSM carriers. HELP PLEEEEEASE!