California State University
Csun: Readability Helps the Level
This California State University Northridge site offers explanations of various methods to determine the readability level of one's writing.
Other
School.discovery.com: Fry's Readability Graph
Fry's Readability Graph from School.discovery.com gives us a comprehensive look at reading levels. The site has a tool that is used to determine the reading level of reading materials.