The amazing people at iPhone Dev Wiki team just released iUnlock. Unlocking the iPhone will allow any Sim card to be used in the iPhone which will cause an increase in sales and was a major goal for the team. After unlocking the iPhone you can easily switch your carrier (AT&T, T-Mobile etc.) by switching out the SIM card. Unlike iPhoneSimFree, iUnlock is Free and the source code is even provided to the public.

In the next few days a GUI version of the unlock software is said to be released as part of Installer.app which will make the entire process a breeze, so if you are feeling wary wait a few days. Otherwise, You can download iUnlock here, here, or here. And you can find tutorials and detailed step by step instructions on installing iUnlock here, here, here, here, here, and here.

Use iPhone mods and hacks at your own risk! Installing 3rd Party iPhone apps requires you to jailbreak the iPhone before installing the native software and apps. You can use Installer.app for Mac OSX and iBrickr for Windows PC to do this. Browse the full list of all iPhone and iPod touch native 3rd party apps filed under the software category.

Get it here