unlock iphone 3g 4.1

[Cash Marines]

I have an iphone 3g with 4.1 firmware, i intalled ultrasn0w to unlock it but everytime i put the simcard in and installed the ultrasn0w program it stared searching and freezing. then i take out the simcard and iphone runs like normal, any Ideas whats happening? thanks

Never mind, I found a way to unlock it.
for all of you who need a tutorial on how to jailbreak and unlock iphone 2g,3g,3gs, firmware 4.1, 4.2.1 by flashing your baseband to 06.15.00 and unlock it with ultrasn0w.

Here is Tutoral: Flashing baseband and jailbreak