Audio Beat Detection Analysis?

An Anonymous Coward with a developing sense of rhythm asks: "I'm a CS student, and I'm interested in audio processing - specifically beat and pitch detection. Whilst there seems to be quite a lot on the Internet about tempo and pitch modification algorithms, I'm having trouble getting anything about the detection field, apart from a few PhD articles. Does anybody have any suggestions of a good place for a undergrad CS student to start? It's a complex subject I know, but I'd like to investigate it further, and am at a loss as to where to start"