With The Call Of Cthulhu being so popular, there are a number of sites that are dedicated to the product. Listed below are some links to sites where more information can be obtained.

• Chaosium are the company who created the the game. Their web location is www.chaosium.com. It contains details of all the modules that were ever produced for Cthulhu, including those that are out of print. There are details of upcoming modules and addons. In addition to Cthulhu, Chaosium also produce other RPGs. All have a definite leaning toward the dark side of the art although I can't comment on their quality since I have never played any of them. They also have a fiction arm which specialises in Cthulhu based horror works and a Cthulhu card game.
• The location of the authorised d20 version of the games is at the Wizards Of The Coast website. Unfortunately they don't seem to be big on Cthulhu and are content to bring out ever more and more Dungeons and Dragons stuff.
• Pagan Publishing produce a number of supplements including the rather good Delta Green, a cross between Cthulhu, The X Files and the real life exploits of the various secret government organisations.

The obvious other place to look for stuff is through the many search engines such as Google or Yahoo. These will direct you to a load of information on Cthulhu.