I won't give all the details or all the rules here. If you want more information, consult the following WWW pages:
Below is my Gess applet. The button launches a separate window containing the board. It should be pretty obvious how to play. It's just a matter of dragging your piece to its new location. Unfortunately, I only implemented it so that two people can play on the same board. An obvious improvement would be to make a multiplayer, networked version of the applet.
I'm sure you'll also find problems with playability and ease-of-use. This code was written in 1994 and is long retired; I have no intention of revisiting it in the near future. The UI isn't bad, and it certainly beats pushing little groups of stones around on a Go board.
Hope you enjoy this applet!