After a successful jailbreak of iPhone 4, Dev-Team just releases latest version of ultrasn0w 1.0-1 that unlocks any iPhone 4 running iOS 4.0.1 (latest iOS update yet). This version of ultrasnow will also unlocks any model of iPhone 3G & iPhone 3GS running on iOS 4.0.1.
But this unlock works for activated iPhone’s only (that mean you have to Activate iPhone with original carrier SIM card).
Here are instruction for unlocking iPhone 4, iPhone 3G/3GS :
1. Your iPhone must be activated with Original SIM
2. Jailbreak iPhone through JailbreakME
3. Go to Cydia and search for UltraSn0w. (If ultrasn0w doesn’t show when you search Cydia, add “repo: repo666.ultrasn0w.com”)
4. Install UltraSn0w
5. Restart iPhone…. that’s it!!!!!!
Now you have an unlocked iPhone 4 with you, that means from now you can use any GSM carrier SIM that was trimmed to fit into iPhone 4.