I finally managed to find the time to complete my puzzle game for Windows Phone 7. This will be my first attempt to publish anything on the marketplace. Let's see how it goes!
If you're interested in how I made the game then I'll be more than willing to share. I might be able to post code directly as this is soon be available commercially, but I can always give some tips and share knowledge. I wrote a step by step article on how to Create a Puzzle Game for Windows Phone 7 using XNA. The puzzle game logic is described in this article and I pretty use the same logic.