The connection seems obvious, but hard to track down. Found a few blog posts with casual references, one pretty good post on the place of Warhol and the Velvet Underground in The Medium is the Massage.
Saw about an hour and 15 minutes of Ric Burn's documentary on Warhol tonight, and Burns came straight from the airport to talk with the 60 or so of us who had gathered. Apparently the whole work is 4 hours--worth checking out.
The McLuhan-Warhol connection that seemed potentially surprising was Warhol's "return to business" after he was shot. He had started out as a commercial artist, abandoned the commercial for the Factory and the art scene, then came back from his near death experience to recognize that "Culture is Our Business," the McLuhan book title from 1970.