First Windows Phone 7 jailbreak by chevronwp7
Unlocking allows the sideloading of experimental applications that would otherwise can’t be published to the Marketplace, such as those which access private or native APIs.
This will allow anyone to unlock any WP7 device on the market using a USB cable and just a couple clicks. This tool is completely safe and reversible for the phone. (The app even allows you to relock the phone.)
As this is first release, you may run into issues. More details at