Patent Offices:

U.S. Patent and Trademark Office
European Patent Office
World Intellectual Property Organization
Japanese Patent Office

Full Image patents:

Micropatent
Optipat, Inc.

Patent search:

IBM Patent Server
Databases of USPTO
Espacenet information - European patents

Others:

PCT-Gazette
Worldwide Listing of Patent Attorneys
Where to find patent information on the Internet
Welcome to Messer - an Israeli goverment organization assisting inventors
InventNET - Inventors Network Home Page