The Five Factors
Bill Connelly's explanation of the Five Factors is here.
I used the Five Factors to review each of MSU's 2014 games, starting with Jacksonville State, and did some explanation.
Heck did some thorough New Math analysis, starting with Youngstown State 2011.
F/+ is a combination of:
Explanation and current rankings here.
Explanations and current rankings here.
Brian Fremeau's page is great in general.
Other Ratings Systems
SpartanDan's projections are here. Massey projections are here. Sagarin ratings are here.