Wombat has given you a
head start on this one.
I have also looked at the Games::Chess modules some time ago and was unimpressed. When I get some more experience I am going to take a shot at improving them.
I have some code at home I wrote a while back that I will be happy to send you too if you want. It's a fully functional chess engine that I wrote in perl. It knows about castling, en passant, and promotion, but it is not that great since I gave up on it soon after I started. ;-/
I love
CPAN!