how can you tell if a business name is registered?

Answer 1

Check the website of your Secretary of State (or sometimes in the Governor's site) if they offer business name search online.

Here are examples of states where you can do a search whether business names are registered

Oregon http://egov.sos.state.or.us/br/pkg_web_name_srch_inq.login
Indiana https://secure.in.gov/sos/bus_service/online_corps/name_search.aspx
Tennessee http://www.tennesseeanytime.org/sosname/
California http://kepler.ss.ca.gov/list.html

Answer 2

I listed some links where you can do some preliminary name checking. However, please be aware that this is merely scratching the surface of what's out there.

Only comprehensive research will tell you if the name is truly available. But, these links are free & a great place to start, so I'd try them out first.

Comprehensive research consists of looking at marks that are similar in Sound, Appearance or Meaning in the pending & registered Federal AND State trademark files as well as the US National Common-Law files.

There are other sites that offer free searching capabilities in conjunction with their commercial services, so I'm not able to post those links due to the Yahoo! TOS. You'll also want to check domain names & yellow pages, so simply do a search for "free domain name search" and "national yellowpages" and the appropriate links will pop up.

Hope that helps! I wish you much success & happiness in all your ventures!