They're kind of far and few between. Carwash.com is the site for Professional Carwahs and Detailing magazine--you can get a free subscription. Carwashmag.com is for Auto Laundry, offers similar free subscription. Those two are mainly for the car wash industry though. There's also a newsletter, Detailer's Digest-- need to subscribe to. I think mobileworks.com has more info about publications.