In this article by Shai Raiten you will see how to create masking using XAML for WP7, WPF and Silverlight.
Source: The Code Project
In the last couple of months since Microsoft has release the WP7 I’ve started to build games and apps in XNA and Silverlight.
Regarding building games it’s different then building applications, especially in UI… and most of the developers don’t like dealing with UI, but UI doesn’t have to be so scary and I’ll start this post with a nice and simple technic I learned when I worked with Photoshop called “Masking”.