Theropods and Birds
This Palaeocast podcast episode (37) can be found at Palaeocast: Ep37. There is supplementary material there, and it's possible to listen on-line from the page.
Additional information
Wikipedia: Theropoda - description (Wikipedia)
Berkeley: Bird origins - description (Berkeley)
Palaeos: Archaic mammals - description (Paaeos)
LiveScience: Dinosaur history - description (Live Science)