Knuffel  
   Windows game based on 'Yahtzee' with a mailing list, chat page, and high scores list.
   http://www.plenio.com/knuffel/

Tim's Yahtzee  
   Single-player 'Yahtzee' clone for Windows with simple point and click play.
   http://www.gonebowlin.com/freeware.html

Yahtzee  
   A version for Windows.
   http://www.rekenwonder.com/yahtzee.htm

Dolphin Dice  
   A Yahtzee game for Windows that features high scores comparisons with others from around the world.
   http://www.johannorberg.se/dolphin/

Yahtzee Master  
   For Windows and Linux, features multiplayer, a computer player and high scores.
   http://www.madmee.eclipse.co.uk/james/yahtzeeonline/