Creating settings and worlds for any RPG is a huge undertaking; here are links to articles and resources to help you along.

Genres and Settings		Last Update
	Fantasy High- and low-fantasy material 4 articles	25 Mar. 2007
	Historical Historical material and resources 2 articles	18 Nov. 2006
	Mapping Cartography Resources for any RPG 4 articles	23 Nov. 2008
	Sample Settings Sample settings with maps and descriptions 2 articles	30 Dec. 2005