U.S. trademarks can be researched using the web database called Trademark Electronic Search System (TESS). TESS is a Web-based trademark database equivalent to X-Search, the USPTO’s in-house trademark database. No matter how your search goes, keep in mind that trade and service mark registration is a legal procedure and should be done in conjunction with an attorney specializing in trademark law.
USPTO Trademark Electronic Search System (TESS)
http://www.uspto.gov/ebc/index_tm.html
USPTO Trademark Application and Registration Retrieval system (TARR)
http://tarr.uspto.gov/
USPTO Trademark Assignment Query Menu
http://assignments.uspto.gov/assignments/q?db=tm
USPTO Trademark Trial and Appeal Board Inquiry System (TTABVUE)
http://ttabvue.uspto.gov/ttabvue/