Get a free copy of Rob Miles' Windows Phone Blue Book and also check out the other books he wrote.
Source: Rob Miles' Blog
As well as getting a copy of my Windows Phone from Microsoft Faculty Connection you can also now get the text in pdf form from http://www.csharpcourse.com/ where it is displayed alongside my other coloured text books.
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.