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ShaagChess is a family favorite! It teaches how to play by highlighting eligible moves and by having various levels of  difficulty--even "random" for beginners! It is better than many commercial versions, and it is the free!

Copyright Scott Haag 2005, distribution permission granted to buildzion.com.

Author's website:   http://gamesbyscott.com/games.htm 

Another good chess game is Jose Chess.

For a tutorial on quick chess strategies like "Kostic's trap", check out www.johnpratt.com/items/chess/menu.html 

Jose Chess is a little more complicated, but it is a great game with advanced features like "Fischer chess" where your players start in a shuffled, random order.

Author's website: http://jose-chess.sourceforge.net