Game design resources
Books:
Game Design Workshop: Designing, Prototyping, & Playtesting Games.
http://www.amazon.com/gp/product/1578202221/
Chris Crawford on Game Design
http://www.amazon.com/Chris-Crawford-Game-Design/dp/0131460994/
Web site, collection of information on game design patterns:
http://www.gamedesignpatterns.org/