Title: Google Patent Search

Link: http://www.google.com/patents
Description: With Google Patent Search, you can now search the full text of the U.S. patent corpus and find patents that interest you. Google Patent Search covers the entire collection of patents made available by the USPTO—from patents issued in the 1790s through those issued in the middle of 2006. Patents issued in the United States are public domain government information, and images of the entire database of U.S. patents are readily available online via the USPTO website.

Title: United States Patent and Trademark Office Home Page

Link: http://www.uspto.gov/
Description: The USPTO is a federal agency in the Department of Commerce, charged, "to promote the progress of science and the useful arts by securing for limited times to inventors the exclusive right to their respective discoveries" (Article 1, Section 8 of the United States Constitution).