If you are interested in developing applications but do not know much about Silverlight or C#, then Microsoft presents a series of videos to help you through their Channel9 network on MSDN. These videos are for absolute beginners but could be used by professionals to brush up their knowledge.
The description on the website reads :
This video series will help aspiring Windows Phone 7 developers get started. We'll start off with the basics and work our way up so in a few hours, you will know enough to build simple WP7 applications, such as a GPS aware note taking application. We'll walk you through getting the tools, knowing what an if statement is, to using the GPS built into the phone and much more!Check out the videos, starting with the introduction video by clicking on the link below.
Windows Phone 7 Development for Absolute Beginners: Series Introduction