Rules of Yahtzee - Includes all the rules of standard play.

Kismet - Rules for a variant of Yahtzee that uses different dice.

Killer Dice from Gypsy King Software - Killer Dice is a Macintosh dice game based on the classic Yahtzee. It includes single, double and triple games. From Gypsy King Software.

Free Comp Stuff - A site offering a free Yahtzee game for Windows and links so you can make your own games.

Yahtzee Games - Reviews of Yahtzee PC games, along with pricing information.