As Gene pointed out, lots on the internet about this. I'm Sure Chapmans covers it well.
The rules come from our Uncle Sam (CFR's):
Electronic Code of Federal Regulations:
Hope this helps
Edit; my link just goes to one part. Maybe this will work. Search in parts 125 to 199
http://ecfr.gpoaccess.gov/cgi/t/text...3/33tab_02.tpl
This is a neat guide about the rules in easy to read form, however it does not cover vessels over 65'. Those rules will be in the CFR's, somewhere.
http://www.uscgboating.org/regulatio..._brochure.aspx
Near the bottom is the link to the guide.