According to "the futon critic" site...
8:20 PM - PRISON BREAK (FOX)
· 1st season finale - special time (PB-122)
and
9:20 PM - 24 (FOX)
· new episode - special time (TWF-522)
because of...
8:00 PM - FOX NEWS SPECIAL: PRESIDENTIAL ADDRESS (FOX)
· special presentation (SP-0639)
I just verified this on the FOX network site!