The New Yashica TLR FAQ: Yashica TLRs seem to be a popular choice for getting into medium format photography, and this seems like a good breakdown of the various models.
Hasselblad Historical: Hasselblad cameras are known as some of the better medium format cameras. This site has more information about them than any one person could possibly need.
Color Film Chart: A brief summary of the properties of various color films.