What rankings is important?

[RunningBackGuru]

Im new to following college football and I was looking at the rankings for the teams. Looking at ESPN (To view links or images in this forum your post count must be 10 or greater. You currently have 0 posts.) I noticed there are two different rankings. One of them is AP Top 25 and the other is USA Today Poll and I was just wondering wich of the two is the one that will determine the national championship game?

[phinphan896]

BCS but they come out after week 6 i think

[Skeet84]

BCS and it has alot of things involved.

[Motion]

BCS but they come out after week 6 i think

Week 8

And it factors in a bunch of different things: Harris Poll ranking, Strength of schedule, quality wins, etc...