World Hum, my portal for travel news, just posted an article I wrote for them called "How to Eat Peking Duck in Beijing." It's part of the site's series of "How to's" that are culturally specific to a given destination.
Included in the article is a bit of Peking duck history, how to order and eat Peking duck, and a list of recommended restaurants in Beijing. It's geared towards the Peking duck newbie, but veteran eaters of kao ya will probably also find it interesting. (I hope!)