The following gateways vary, but generally, simply entering a domain name on the query form will yield a record for that name. Entering company names, individual names, e-mail addresses and other queries may also yield information. WHOIS provides a good way to investigate prospective names to determine which are already registered, and to find what companies or persons are associated with a domain name.
Web-based WHOIS Gateways
Various gateways at North American commercial and academic sites:
European and other international WHOIS gateways
WHOIS servers list: