Here is some more reposting. This time it comes from Boing Boing with a great how to for cold brew coffee.
Essentially, its a lot of coffee coarsely ground as if for a French Press. You put it in a nutbag, which is like a bag made from a tightly woven cheesecloth.
You let to sit in cold, filtered water overnight, and it is ready for the next day.
I just need to track down a nut bag and give it a shot.