I read this on Sportsline and ESPN and some of it is confusing. This article lays it out better I think Rest of the article at. Six Bowls In Playoff Format
It appears that the NC game is not limited to the site of the 6 major bowls. This leaves the door open for Jerry World in Dallas and northern domes such as Detroit and Indy. When the Rose Bowl is a semifinal, it won't necessarily be hosting a PAC or Big Ten team. Things are going to get complicated.
It took a while, but I figured it out. Basically, there are going to be six "major" bowls instead of the long-time traditional four. Two of the six will host the 4-team playoff games on a rotating basis. The other four will represent what the original, traditional four did in years past. The new wrinkle is that one team from the "gang of five" (my words, the Big East and four non-BCS conferences) will automatically be eligible for one of the four non-playoff bowls. The Big East no longer is considered a single BCS automatic qualifier conference. It now is one of the gang of five, which is as it should be.