You will now be able to officially jailbreak or unlock your Windows Phone mobile devices using the ChevronWP7 service. ChevronWP7 have launched a new website offering a Windows Phone developer unlocking service to developers across all skill levels and regions for USD 9 per phone.
To begin with, you will have to sign in and register with a Windows Live Hotmail ID. Once done, you will need to purchase Unlock Tokens. You can make the purchase using your credit card or PayPal. One token will let you register one Windows Phone mobile device.
Once these formalities are complete, you can download the Unlocking Tool.
Using this tool, you will be able to install homebrew XAP apps on your device. It will also allow users to run their apps outside the Windows Phone Marketplace.
The ChevronWP7 team has worked closed with Microsoft in developing and releasing this tool and you can register for it here.