How do I know if a domain name has already been registered?
How do I look up a domain name?

You can search the Domain Registration Database by doing a search on the "Whois" database.

Point your browser to http://www.fasterWhoIs.com (the Whois that powers our domain search form) or http://www.nsiregistry.com/, which is the Shared Registry of all InterNIC Registrars, and enter your desired domain name. If the domain is available, the results page will display the "No Match Found" message. If it is no longer available, it will display the domain's Registry information.