You can find it on iTunes. There are three professors who teach at various times that are all very competent, but Urnov's lectures especially captivated me. I wonder if he will discover one of his mysterious podcasters with a google search ;-)

Molecular and Cell Biology 140: General Genetics - Fall 2007 Audio

Fyodor Urnov, G. Garriga, R. Brem

Note: These people speak very fast.