In a nice demonstration of just how easy it is for Silverlight developers to port over their creations to Windows Phone 7, the developer of the classic online game 'Zero Gravity' has ported brought over his creation for our new OS. He had this to say about the process:

What amazed me the most out of this whole experience is that the codebase written back in WPF/e was able to be recompiled with very little modification into the latest version of silverlight

You can read more on Ryan's game here and if you want, you can just play the game right now online by going here: http://zerogravity.terralever.com/  We just love the cartoony graphics.