unlock iPhone 3g

[dhruv227]

i have bought a new iPhone 3g from usa, but i am an indian and want to use it india and it's locked, umm how do i unlock it here on my own.

[Smith6612]

There are various sites around on the internet which would help you hack the iPhone to unlock it so that you may use SIM Cards in it. It has something to do with booting it into recovery mode, while having it plugged into your PC, where your PC is running a program to upload software to the iPhone while it is booting into Recovery Mode (which means one thing: Shell Access!). This is one thing I can say, at least on the iPod Touch side.

[adamparkzer]

There's a lot of results on Google for unlocking iPhones, and there are some websites that even sell software that do it for you automatically. I came across this, which might help:

You will need your iphone 3g jailbroken with the latest firmware at the time (2.2) if you already have this, restore it via itunes, and then go to the step #3.
Step #1: You will need to update your iphone to the latest firmware. You can do this with itunes, connect your iphone 3g, and choose update. This will update also your baseband, that´s what we need.
step #2: After you have updated your iphone 3g, you will need to jailbreak it with quickpwn. here you can find the guide to use quickpwn, use the same steps as the iphone.
step #3: When your iphone is jailbroken, its time to unlock it. You can use installer or cydia, add the following source:
CYDIA: http://apt9.yellowsn0w.com
installer: http://i.yellowsn0w.com
install it, and reboot your iphone with the sim installed. Wait about 90 seconds, and if you can´t still see your carrier, pull the Sim and try again.

The text is copied from here, and you can probably find a lot of other guides just by using Google.