Here are the last three BCS title game ratings:
2011 championship game between Auburn and Oregon on ESPN: 15.3 rating, 27.3 million viewers.
2010 championship game between Alabama and Texas on ABC: 17.2 rating, 30.2 million viewers.
2009 championship game between Florida and Oklahoma on FOX: 15.8 rating, 26.8 million viewers.
The highest all-time BCS-rated game was the classic 2006 Rose Bowl between USC-Texas – arguably one of the best games in college football history – that ended with the Longhorns winning, 41-38. It generated a 21.7 rating and 35.6 million viewers.
My guess for Alabama and LSU: a 16.1 rating and 28.4 million viewers.