College Football BCS question

What are the formulas used by the computer polls to determine rankings? Are they kept secret?

This link at HowStuffWorks has a helpful explanation of the entire byzantine BCS ranking system, including what factors each of the computer polls depend on, as well as links to each computer ranking.

Some of the computer rankings are propietary, but I think that everyone has reverse engineered them (not the right use of the phrase I know).