The Windows Phone marketplace may not really be as fussy a place as the iPhone App Store when it comes to accepting new applications. But again, not all the apps you may need are on the app marketplace yet. If you are looking for more freedom in this aspect, it is now possible to jailbreak your Windows Phone 7 handset with one simple application.
Called ChevronWP7 unlocker, this is a software that you should install on a Windows computer running XP SP2 and above. All it takes is for you to connect your WP7 phone to the computer and a couple of clicks on the application. Doing this will let you access any of the several experimental apps that may not be available on the App marketplace because they use private or native APIs.
Go ahead and check out the software and instructions in the ChevronWP7 website.