There are many tricks available to unlock iPhone.
Here are some tool to unlock iPhone
This are 4 tools to unlock iphone.
1.iPhone Unlock Toolkit
This toolkit has total solution for unlock iPhone and enable GPRS and RSS feeds
2. iPhone.unlock.no
This is a software. By this software you can also unlock your iPhone.
3. Pwnage
This tool is also use to unlock iPhone 3g .But it is not useful for iPhone’s latest of firmware.
Also Read IPhone Tricks
Also Read IPhone Tricks
4.Yellowsn0w
This is an updated version of Dev team’s original software which unlocks and jailbreaks iPhone. When old versions caused some inefficiency, this latest version runs smoothly.