I am trying to build a chess application. I have the backend logic in place (almost). But I havent worked much on UIs. I plan to use C# and I hear WPF is the way to go.
ComponentOne has a a Silverlight demo of this board game called checkers. You can view this demo online and the source code is available for free. Definitely, it can be a lot helpful for you to get started. Note that porting to WPF would be rather easy.