International Patent Searching

  International IP Treaties (WIPO) European Patent Database Network

  espacenet.com (European Patent Office patent searching site)

  Singapore IP Office Int'l Search Surf IP (Singapore IP Portal)

  Delphion intellectual property network - international and US ... This is probably the finest and most sophisticated patent database website.  It can do all kinds of incredible things like ranking, proximity searching, data analysis, special charting, watches and watch notices, etc.  But, it is quite expensive.