A whopping 30 million patents can be searched at esp@cenet, a free database run by the European Patent Office (EPO). Although it covers 63 countries, including Japan, some listings include only bibliographic info or abstracts. You’ll find full text and images for EPO, World Intellectual Property Organization, and U.S. patents.
Patent bonanza.
This is very up-to-date information. I think I’ll share it on Delicious.