the first few hits seem to be saying that tobacco is regulated for minors by the FDA. Other than that, there isn't any regulation on adults by the FDA or other organization. I assume "regulation" means that adults aren't limited to the amount of tobacco they can purchase/consume unlike drugs like vicotin (sp?) and other controlled substances. Minors however, thats aother story i think...no billboards within 1000 feet of schools, ad campaigns, etc. etc.
just a guess....read through the google hits and look for articles.