About.com - Annotated links to a variety of Monopoly resources, including where to play online, the game's history, and information for collectors. - http://boardgames.about.com/msub19.htm
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. - http://www.monopoly-man.com/
Monopoly Collector - Game history, facts about different versions, site owner's collection, official rules, and some sales. - http://www.monopolycollector.com/
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. - http://www.psmonopoly.com
Durango Bill's Monopoly Probabilities - Statistical and graphics data for End-of-turn, Land-on, and per-dice-roll Monopoly probabilities. - http://www.durangobill.com/Monopoly.html
Monopoly Rents - A table of costs and various rents in the UK version of Monopoly. - http://www.jdawiseman.com/papers/trivia/monopoly-rents.html
Probabilities in the Game of Monopoly - Includes land on frequencies, expected earnings, and payback times. - http://www.tkcs-collins.com/truman/monopoly/monopoly.shtml
Monopoly Lexicon - Photographs and literature for collectors. Also features an index of country-specific game editions. - http://www.muurkrant.nl/monopoly/index.html
Who Invented Monopoly? - A collection of articles about the classic board game's claimed and actual origins, and photographs of early game pieces. - http://www.adena.com/adena/mo/index.htm