Mac OS X chess playing software?

Does anyone have a recommendation for a chess program that will play natively (not in Classic mode) in Mac OS X Leopard?

It seems like there's been an explosion of stuff using the Fritz interface in recent years, but nobody's bothered to port anything to my beloved Mac..

I'm not sure if this is correct but check out this link on chess.com

http://www.chess.com/download/view/sigma-chess-61

Thanks, Zanmi

I am testing this program... It's seems to be very good.

oruam,

 Mac OS X has always been renowned for its program, "Chess."  Open up spotlight with command(the apple key)+space and type in chess.  One may customize the board, use speech tools - i.e. talk in commands to move pieces -, and set the artificial intelligence's difficulty.