General Information on Patents by the USPTO: 

USPTO Brochure for Provisional Patents:

Guide to filing a Utility Patent Application (non provisional):

USPTO's links to other patent websites: 

Online USPTO Keyword search of patents since 1976:

Google Patent Search:

USPTO describes the difference between Patents, Trademarks, and Copyrights:

USPTO offers general information on Patents:

USPTO web page on invention promotion company complaints:

National Inventor Fraud Center:

USPTO search for Patent Agent or Patent Attorney: