European Trademark Office — European trademarks, practices and procedures, legal aspects, and databases.
United States Patent and Trademark Office — Patent and trademark information, including links to forms, fee information, news, legal materials, statistics, and related Web sites.
USPTO Trademark Electronic Search System (TESS) — Contains more than 4 million pending, registered and dead federal trademarks
USPTO Web Patent Databases — Full text database, bibliographic database, AIDS patent database.