Worldwide Patent Database [1]
Searchable database of patents on file

More Patent Databases (industry and country-specific) [2]

FIling for a provisional patent [3]

US Copyright Office [4]
Promotes protection for the arts and for authored works

US Patent and Trademark Office [5]
All about patents, trademarks, copyrights, and inventor resources and support.

US Trademarks [6]
The official (and searchable) US Code on trademarks posted by Cornell Law School

World Intellectual Property Organization [7]
Promotes the protection of intellectual property throughout the world

National Institute of Standards and Technology [8]
Advancing measurement science, standards, and technology