* www.copyright.gov allows you to search U.S. Copyright registrations.
* TESS allows you to search federal trademark applications and registrations.
* sos.state.tx.us allows you to search Texas State trademarks for a nominal fee (apprx $1/search). For access, you must either register or sign up for a temporary account.
* www.uspto.gov allows you to search U.S. Patents and published patent applications.
* www.wipo.int allows you to search PCT patent applications.
* ep.espacenet.com allows you to search patents and patent applications worldwide from 81 countries.
* www.freepatentsonline.com is a free (ad-supported) resource that allows one-site searching of the USPTO, PCT, and EP databases. With a no-cost registration, you gain access to several nifty features including easy PDF downloads and saved search results.