All windows phone users know how irritating it is when you’re messaging or using your phone while lying down and the screen orientation keeps changing as you keep moving.
Holding the phone in one position is very irritating. Unlike android users, we can’t put the rotate screen option off. However if your phone is interop/dev unlocked or you can side load applications using a XAP deployer,you can install the app orientation lock created by windowsphonehacker. Its adds this basic functionality without any frills…a simple slider switch for on and off.
Simply hold the phone such that the screen orientation is the one you want and slide the switch to lock. Now you can rotate your phone as much as you like and still not worry about the screen constantly rotating.
Watch the demo and read more or download the xap here- Orientation lock