Here is a link to a site with loads of info. Don't worry that it is a bichon site; most of the essays apply to ALL dogs.

http://www.bichonfriseusa.com/index....ational%20mark

Scroll down, watching the middle column. You will see a heading "PUPPY INFO" Under that, is one essay "housetraining 101." Within that essay is a section on crate training. It is much as Binka nugget explained.

Hope that helps.