Perhaps start by drawing a chessboard...
A loop or two, using rect() and fill() should do the trick.
You can also use SVG for the chess pieces, Wikipedia, among others, has such files.

here...


http://www.openprocessing.org/sketch/31784


Chess with 3 different sets of Figures.

Runs only in Chrome (or offline).

Change the set of figures by Cursor Up.

I think the fields of the board (not the pieces) can be clicked with the mouse



Cheers,

Chrisir