Not that I know anything about college football, but when Texas had the ball around the 20 with 45 seconds left, all I could think was - they really should let them score on the next play and give Leinart enough time to work with. USC was only down three after the two-point conversion, and 40 seconds or so probably would have been ample time, given that they almost did it in 16 seconds.
Just seemed foolish to rely on the defense which got shredded all game, rather than the offense that racked up over 500 yards. I know letting Texas score would look bad, but do you want to win the game or not?
The counterargument is that Texas almost didn't make it - needing to go on fourth down, but it seemed that two of those plays - designed pass plays in the end zone were completely stupid when Young could run for seven or eight yards at will. Why not just roll him out every play and let him make up his mind on the fly? Which eventually they did, and he scored.
In any event, the "let them score" strategy when you're up by less than a score to get the ball back is taboo for obvious reasons, but there are certainly cases where it's the best chance you have to win. Today's game, you could argue either way, but if a team were up one, and their opponent had the ball at the 10 yard line, first and 10 with 2 minutes left (and no timeouts)- clearly you let them score.