Correction. It's the agreement that SIX conferences agreed to, and it's far from perfect. The reason for this agreement? Well, of course, greed and money. The six conferences would have to share the money (although a bigger pot) with schools outside of those conferences, instead of getting the guaranteed money they currently receive and is kept away from the other schools. No excuses should be made for the lousy system we currently have with BS (pun intended).
They are one and the same. The presidents of the university control the conferences. If USC doesn't like being part of the PAC-10 then they can break away.
If USC doesn't want to be part of the BCS then why did they play in BCS bowls the last 3 years?
Auburn signed on to the agreement so they have nothing to complain about last year despite going undefeated. USC signed on to the BCS so they have nothing to complain about in 2003.
BTW, the Rose Bowl and PAC-10 signed onto the BCS late - I think two or three years after its inception. The PAC-10 had plenty of time to study the BCS and decide whether it wanted to join or not - its member schools decided it was a good idea. It's not a great system, but it is the system that the PAC-10 and its member schools signed on to.
USC can go along with the system when it suits them and then disavow it when it is inconvenient. USC should not have accepted the BCS trophy last year if it didn't want to be part of the system.
And another thing, the BCS doesn't bring the bigger schools any more money than the old system. Teams from the big conference dominated the bowls in the past anyway.