iPhone Dev-Team has updated UltraSn0w unlock for iPhone 4, 3GS and 3G to version 1.1-1. UltraSn0w 1.1-1 fixes the poor standby battery life for all those who unlocked iPhone 4, 3GS or 3G with earlier UltraSn0w 1.0-1 version.
If your iPhone battery drains pretty fast even on standby after unlocking with UltraSn0w 1.0-1, then you’re advised to install UltraSn0w 1.1-1 update from Cydia.
ultrasn0w upgraded to version 1.1-1 we’ve tweaked a few things that may help with standby battery life, you can upgrade via Cydia.
Here are a couple of before & after screeshots shared by Sherif Hashim:
Unlocking iPhone let you use SIM from any carrier. Steps to unlock iPhone 4, iPhone 3GS and iPhone 3G remains same. Step-by-step guide to unlock all iPhones can be found here:
How to: Unlock iPhone with UltraSn0w