The 2001 decision referenced below is big. Also, some of what I cut & paste has lost their embedded links. If you send me an email to jim.lande (at) fcc.gov I will forward it to you. I think that a lot of broadcast regulations are in Part 73 of the CFR 47 and can be found at http://www.access.gpo.gov/cgi-bin/cfrassemble.cgi?title=200847
FYI John is an attorney in Media and has taught telelcommunications policy at GMU Law School.
Here is the principal statute, the principal regulation, and a 2001 decision that I think is still authoritative.
18 U.S.C.A. § 1464
United States Code Annotated
§ 1464. Broadcasting obscene language
Whoever utters any obscene, indecent, or profane language by means of radio communication shall be fined under this title or imprisoned not more than two years, or both.
47 C.F.R. § 73.3999
Code of Federal Regulations
Title 47. Telecommunication
Chapter I. Federal Communications Commission (Refs & Annos)
Subchapter C. Broadcast Radio Services
Part 73. Radio Broadcast Services (Refs & Annos)
Subpart H. Rules Applicable to All Broadcast Stations (Refs & Annos)
§ 73.3999 Enforcement of 18 U.S.C. 1464 (restrictions on the transmission of obscene and indecent material).
(a) No licensee of a radio or television broadcast station shall broadcast any material which is obscene.
(b) No licensee of a radio or television broadcast station shall broadcast on any day between 6 a.m. and 10 p.m. any material which is indecent.