As I wrote in
As of today, three of the four at-large berths figure to go to the SEC Championship Game loser, a 10-2 Big Ten team (most likely Iowa or Penn State) and TCU (assuming it wins out). If Oklahoma State (8-2) wins out, the Fiesta Bowl would be unofficially obliged to select the Big 12's Cowboys to replace Texas. If they lose, however, there should be a spot waiting for the Broncos.
The BCS matchups will depend in large part on what that Fiesta Bowl does with that replacement team. There's some thought the bowl would want the highest-ranked team, No. 4 TCU -- but not if it means matching up TCU and Boise. A more realistic scenario is that the Fiesta takes Iowa (assuming it beats Minnesota next week), which has never played there and figures to bring a huge crowd. If it doesn't, the Orange Bowl will almost certainly snap up either the Hawkeyes or Penn State.
• Note that I'm currently projecting Georgia Tech (ACC) and Pittsburgh (Big East) as conference champions. If Clemson wins the ACC, the Orange would want to avoid a TCU-Clemson rematch and would probably take Pittsburgh instead. If Cincinnati wins the Big East, the Fiesta may choose to pit undefeated teams TCU and Cincy, leaving Penn State/Iowa for the Orange.
• Finally, it's important to remember that bowls are NOT obligated to choose their teams in exact order of conference standings. For instance, "ACC No. 3" means "third choice of ACC teams" -- not "the ACC's third-place team." Also, a bowl can only select a 6-6 team from a conference if no 7-5 team from that league is still available, and bowls seeking a replacement for a conference without enough eligible teams cannot choose a 6-6 team if there is a 7-5 team available.