http://www.google.com/patents
http://patft.uspto.gov/
http://gb.espacenet.com
http://www.pat2pdf.org/
http://www.patentlyo.com/
http://www.patentbaristas.com/
http://www.ipwatchdog.com/
http://www.google.com/advanced_patent_search
http://assignments.uspto.gov/assignments/q?db=pat
http://www.uspto.gov/patents/index.jsp
http://www.copyright.gov/
http://www.uspto.gov/trademarks/basics/index.jsp