Keep Your Copyrights
Copyrights are the lifeblood of photographers. The basic rule is that if you are not an employee and take a picture, then you own the copyright, if not it's your employer that own the copyright.
The US copyrights laws are being rewritten, and it affect all of all. One of the best resource is: Keep Your Copyrights from legal academics at Columbia Law School, one of the most prestigious US law school.