I assume you also mean on the federal level? Because if you want to get into state and local laws, then you're looking at thousands.
There really isn't much I could tell you that the NRA-ILA site and GunCite don't do better, so just check these out:
http://www.nraila.org/GunLaws/Federal/Read.aspx?id=63
http://nraila.org/GunLaws/
http://guncite.com/