I've mentioned posts at WFMU by Kliph Nesteroff a couple of times here ( Woody Allen and Henry Morgan). He writes exhaustively detailed articles about comedians and comics from years ago.
And he gave a fascinating interview with Marc Maron on the WTF podcast. It's up here (or here) for a while. In it he covers some lesser known comics (such as Jack Carter and Shecky Green), and spins a fascinating tale about a chauffeur who became a comic with help of the mob, and lost his career when mob families changed.
Mesmerizing discussion of art and the laughter industry of a bygone time. It's not very funny, but it's fascinating.
Kliph's posts at WFMU are collected here, and he has his own blog, including interesting video and audio tidbits, at Classic Television Showbiz.