Ahhh... good question.

As for our divisions (1-A, etc), those are determined primarily by size. If you have a student body that is small, you'll belong to a smaller division. The BIG schools are pretty much all 1-A. It is theoritically possible to move up, but rarely happens.

The conferences started out long ago as regional things. The SEC, or Southeastern Conference, was composed of team from the southeastern United States. The Pac-10, or Pacific Ten, was composed of ten teams from the Pacific coast. They still hold pretty much true today, but exceptions are being made. The Big Ten is eleven schools scattered from Wisconsin to Pennsylvania. Go figure.

The Bowl games are post-season games. You have to qualify to get to one, but qualifying for some bowls is just not having a losing record. You have a lower tier set of bowls that invite mediocre teams to play in a mediocre game. The Humanitarian Bowl comes to mind. The 'Big' Bowls normally have some kind of impact to the season. College football has what is called the BCS, or Bowl Championship Series, where a computer takes many multiples and spits out the top teams. (Multiples like strength of schedule, strength of opponets schedule, common opponets win / loss record, home wins, etc). At the end of the season, the teams ranked #1 and #2, as ranked by the BCS computers, play each other in one of the BCS Bowls, the Sugar, Orange, etc, for the National Championship. But sometimes, the computer will rank the teams weird. A computer can't distinguish a loss early in the season when you had a few injuries to a team that wasn't very good at the time from a loss late in the year to a very good team. Let's say Miami, usually a very good team, lost their starting QB for a few games. They travel up north and play a so-so team that has a losing record. But due to the weather and the injury, they lose. The BCS computers will show that as a loss to a team with a losing record and severly penalize Miami, while us humans will see it somewhat differently and will give Miami the benefit of the doubt. And say Miaimi was undefeated and it was their last game. The computers may knock them to #3 and they won't be able to play in the Championship game because of it.

Us humans, a lot of us anyhow, have been clamoring for a play-off format, but the powers-that-be se the BCS and the hundreds of meaningless bowl games as a better way to make $$$ and thus a better system.

I hope that helps. I'm sure someone will chip in what I may have missed or screwed up. But thats the basics...