About.com: Annotated links to a variety of Monopoly resources, including where to play online, the game's history, and information for collectors.
CNN Money: Monopoly to roll the dice and change its board: News article describing the new Then and Now edition of the game.
Dribbleglass.com - Monopoly Cards We'd Like to See: Spoof pictures of Community Chest and Chance cards.
Durango Bill's Monopoly Probabilities: Statistical and graphics data for End-of-turn, Land-on, and per-dice-roll Monopoly probabilities.
Monopoly Collector: Game history, facts about different versions, site owner's collection, official rules, and some sales.
Monopoly Lexicon: Photographs and literature for collectors. Also features an index of country-specific game editions.
Monopoly Man: Presents a description of the game pieces, an overview of the rules, and the game's history. Also includes commentary on variants, offshoots, and spinoffs.
Monopoly Rents: A table of costs and various rents in the UK version of Monopoly.
Monopoly World Cup: Annual online tournament site. Includes winners, a schedule, and a forum.
Monopoly.com: News, merchandise, history, tournaments.
Probabilities in the Game of Monopoly: Includes land on frequencies, expected earnings, and payback times.
PSMonopoly.com: Features calculator tools to determine a player's net worth based on the properties they own, and also a tool that calculates the probabilities of landing on certain properties based on where the player is starting.
Richard's Monopoly: Contains a list of Richard Wilding's collection, as well as links and a wanted page for buying and selling items.
Washington Free Press: Anti-Monopoly: A professor and a freelance writer are determined to set history straight on the origin and theft of a favorite American pastime. By Burton H. Wolfe.
Who Invented Monopoly?: A collection of articles about the classic board game's claimed and actual origins, and photographs of early game pieces.