I had an interview long time ago when I was young and just started programming. I had been showing my badly written battleship game to a skilled guy in his office. It was written in Delphi but with Pascal one-big-function style and it wasn’t double buffered so it has known rendering problems. I said then “You see, it is not a chess, but..”.
In a few weeks I started writing my own chess. After 2 years they were rewritten 3 times and now they are implemented in C# using bitboards (chessboard in 64-bit integer).
There’re some tests for AI engine, graphics in WPF, svg’s for chess figures and a lot more.
Checkout at a GitHub page!
I have found a lot of interesting materials while writing Queem which have one leader – chessprogramming wikipedia. It contains everything you want to begin write your own chess.
There is also nice web page about Rebel, great chess program.
And a list of materials about chess programming.