Android supports sideloading of applications (ie. non-market software). But it is not the first mobile OS to do so – Microsoft (Windows Mobile), Nokia (Symbian) etc. all allowed non market apps. However, with Windows Phone 7, their latest mobile OS, they have gone the opposite route to Android, and taken Apple’s closed app store route. Windows Marketplace is the exclusive, official app store from which you can install apps.
WP 7 is similar to iPhone in that respect – it is locked down (jailed). The notable exception to this rule is developer’s phones, which do not have such lock downs for obvious reasons. However, not everyone can get a developer phone just to sideload apps.
However, the hacker community has come up with workarounds for WP7, as in case of iPhone. A tool called ChevronWP7 now lets you jailbreak / unlock Windows Phone 7 devices. ChevronWP7 lets you bypass the WP7 Marketplace, and thus makes it more like Android – open, allows sideloading of apps and perhaps even third-party app stores in future (like the Cydia app store on iPhones post-jailbreak).
The way this hack works is by fooling the system to believe that your WP7 phone is a developer’s phone. This means that the user can do everything a developer phone can – including sideload apps that are not available on the Windows Marketplace.
ChevronWP7 runs on Windows XP SP2 and later. This Windows Phone 7 jailbreak tool is only for the apps. This does not work to remove or unlock your carrier lock on the phone in any way.
Update: After talks with Microsoft, ChevronWP7 has been pulled by its developers. The Chevron team has promised that it will work with Microsoft to find a way to unlock Windows Phone OS, with their blessing.
Update #2: The Chevron WP 7 team has released ChevronWP7 Labs, which help you to unlock your mobile phone, but at a fee ($9) – small enough to be palatable for most users looking to unlock their phones.
Visit Chevron WP 7 Labs to unlock your Windows Phone device
Or, get the older FREE ChevronWP7 tool ChevronWP7.exe (mirror link) – this is provided as is. If you want a free method, this is worth trying.
Note that the files for free version of the tool may be removed, let me know if that happens and I’ll post other links.