The Washington Post
The Washington Post: Official Laws of Badminton
Official rules and regulations of Badminton from the United States Badminton Association.
PE Central
Pe Central: Pe Lesson Ideas: Badminton 4 Square
At this website, find ideas for a gym-class badminton activity. The modified version of badminton described here is very similar to 4-square and is accompanied by ideas for modifying the game-play.