The www.FastUnlockiPhone.com Team has just released FastSn0w 0.9.4 to jailbreak and unlock iPhone  4 and 3Gs 4.3.3 . You can update to iPhone 4.3.3 firmware if you want to  unlock iPhone 4 and 3gs version 4.3.3. This is because the new iPhone 4.3.3 firmware updates baseband to 05.12.01 on iPhone 3GS and iPhoneG which makes it possible to jailbreak and unlock iPhone 3GS andG.

For More Information to unlock your iphone visit the official website www.FastUnlockiPhone.com

If you need a carrier unlock, FastSn0w from www.FastUnlockiPhone.com will handle the unlock and jailbreak for iphone 4.3.3. For the 3G and 3GS, use Cydia after you’re jailbroken to install fastsn0w.
It uses our original Pwnage bootrom exploit for iPhone 2G, iPhone 3G, and iphone 4 and iPod 1G. (Because it’s a bootrom exploit, it can’t be fixed by Apple without a new hardware release.) Note that FastSn0w 0.9 does use the USB exploit for iPhone 3GS and iPod 2G running 4.3.3, but that exploit will be fixed in Apple’s next FW release.
It offers custom logos and verbose boot
It installs Cydia without needing a separate download
It’s not as fast :) (but FastSn0w handles more variations :) )
What if I have a late-model device?
If you have a late-model iPhone 3GS and iphone 4, or if you have an iPod touch 2G whose serial number begins with “MC”, you can use FastSn0w to jailbreak . That means you will not need to connect your device to a computer to complete the boot after a reset.
FastSn0w will ask you whether or not you fit in this category when used with the iPhone 4 3GS or iPod touch 2G. If you have a late-model device and don’t give FastSn0w the correct answer, you will likely need to do a system restore to recover from the mistake.
To do a tethered boot after your late-model device resets for some reason, either run FastSn0w again and select “Just boot right now”, or run fastsn0w.
The instructions posted here almost similar to the one we posted earlier with FastSn0w 0.9.3 for iPhone 2G and iPod touch 1G/2G. The only difference here is that we are using the latest FastSn0w 0.9.4 from Dev-Team which is specially released for this firmware update.
We strongly suggest that you stay away from this official upgrade until and unless the DevTeam or George Hotz releases new jailbreaking and unlocking tools for 4.3.3 firmware. We will let you know when it will happen. In the meantime you can follow our complete jailbreaking and unlocking guide for iPhone 3.1.2 firmware using blackra1n, PwnageTool, FastSn0w, sn0wbreeze, ultrasn0w and blacksn0w.