Eff whatever you're doing right now and waste some work hours with these fascinating reads from around the interwebs from people who know more about Mad Men than me. Stick around, the best links are at the bottom.
Advertising Age has a nice piece about their appearance in "Public Relations," the first episode of the season.
The Oregonian has a fairly superficial article about Portland company Jantzen, the "family company" that appeared in the same episode.
The bloggers at Basket of Kisses are scary fanatical about the show but if you like really, really deep anal...ysis you'll love their posts.
And finally Tom and Lorenzo, who maintain a fantastic blog on style and fashion in television and movies, have provided some of the most in-depth, contextualized analysis of the clothing and decor on Mad Men that I've ever seen. Be sure and click through their episode by episode run down of the women's clothing and character arcs from the first three seasons. This is amazing stuff.
Take that, day job!