Activity Planner: Card Games  
   A list of card games that can be played with a standard 52 card deck. Games for children from age three to eight. Includes number of players, ages, length of time a game takes, and the rules.
   http://www.parentcenter.com/general/fun/games/7410/7454.html

USPlaying Card Company: Children's Card Games  
   Has instructions on how to teach children how to play card games, and the rules for several games for children from 4 to 12 years old. Gives the number of players, suggested age range, and skill level for each game.
   http://www.usplayingcard.com/gamerules/childrenscardgames.html

Card Games by by John McLeod  
   A collection of dozens of card game rules arranged alphabetically, categorically, and geographically.
   http://www.pagat.com/