how to check few thousands domain names?
 

on availability

any registrars with such bulk option?

http://www.softnik.com/download/

Domain name analyzer and the pro version

If you don't need any actual data, but just a yes/no if its registered, couldn't you script something with nslookup, host, dig or something like that just to see if it will return name servers?

Most whois servers don't like getting a couple hundred hits in a row, but most dns servers could care less.

thanks for that link :thumbsup