Take a look at this quick blog post of Rob Miles on
Windows Phone 7 Screens and
XNA Games.
Source: robmiles.com
If you are writing games for Windows Phone there are a couple of things worth knowing about how the display works.
Firstly, the top bar of the screen is used to display things like battery level, signal status and the like. This status bar only appears when the user touches that part of the screen, which is good because it makes the whole of the screen available when you don’t want to know your precise signal strength.