I have of now; checked each and every version starting from 0.90 and 0.96! I got my 3g iphones to work on all of them. I have my guide here http://www.hackint0sh.org/forum/showthread.php?t=61855 (It was for the older versions- Hopefully you wont need to use anything with the latest version)
I must say that 0.96 is by far the most error free version. I installed it through Installer. Wait for it to download. Reboot your phone and thats it! no need for anything.

NOW; my phone was working perfectly . calls in/out data and sms but i upgraded to 0.95 and i started getting the call failed error for outgoing calls. I restored my phone; tried and installed all the previous versions one by one but no relief. Still call failed. I installed 0.96 and everything perfect except for the outgoing calls. So after two-three days something occured to me. I went into settings and then phone and tap the show my caller id settings. It turns out the show my caller id tab was off. SO i turned it ON and voila!!!!! I can make outgoing calls now! I turned my caller id off and tried making calls and started getting the Call failed error again! I have tested it on 4-5 different 3g iphones now and the same result. The show my caller id has to be ON!! and the calls out start working again.

I'm in Pakistan as well and I've been having the call failed issue since 0.91. I'm using Warid Tel on 0.96 now, and everything works perfectly including incoming calls, however I still can't get outgoing calls to work. I tried your method posted above, however my phone doesn't give me the option to turn "Show my Caller ID" On/Off. The On/Off button is somewhat greyed out, basically locking into always being on. Any advice?

I am on Telenor but I just tried it on a Warid sim and I could make outgoing calls after tapping the method. Have you tried tapping the on/off button even if its greyed out? When you upgraded to 0.96; did you do a fresh restore and installed 0.96 or just upgraded to 0.96. It always helps to do a fresh restore.

I tried tapping the button, but it doesn't do anything and remains ON. For each time yellowsn0w has been updated, I simply uninstall it through Cydia or Installer, and reinstall the current version. By fresh restore, do you mean I should completely reinstall the firmware on my iphone? I'm at 2.2 right now w/ 2.28 base.

Originally Posted by CouchKing

By fresh restore, do you mean I should completely reinstall the firmware on my iphone? I'm at 2.2 right now w/ 2.28 base.

Correct.

AG

Originally Posted by aghazi

Correct.

AG

Ok can I just quickpwn it again? Or do I need to restore it to normal 2.2 and then quickpwn it?

Originally Posted by CouchKing

Ok can I just quickpwn it again? Or do I need to restore it to normal 2.2 and then quickpwn it?

I recommend a clean restore from iTunes, quickpwn, install 0.9.6 from Cydia.

AG

Here is what I did few min ago. I am on Telenor PK. Working fine.

I was on 2.2 FW with 1.48 BB. I was using universal-sim.

-Removed SIM
-Use Option+Rectore (on Mac). Selected firmware.
-After iTunes finsihed restore and initiated reboot on iPhone, quicky closed the iPhone and killed iTunesHelper task from using activity monitor. Use Task Manager in win. I do not want iTunes to perform any action before quickpwn.
-Quickpwnd. Rebooted.
-Used Cydia to install 0.9.6.
-Rebooted
-Inserted Telenor SIM
-Quickly checked, no service. Turned on Show My CallerID
-Rebooted iPhone. DONE! Full signal with Edge icon. Calls in/out working.
-Connected iPhone to iTunes.
-Backup restore in progress.

AG

I just did almost exactly the same as you, and I still cannot make outgoing calls. My "Show caller ID" is still greyed out (in the ON position).

No offence Ghazi but there is no need for the sim to be out. The sim can be inside all the time. Secondly no need to play around with the Caller ID setting till you get signal.

CouchKing- I tried my moms Warid sim card. It works. Do you want try a different warid sim card?