This is the free script with completely default settings (opens in a new window).
This is the pro script with the affiliate link enabled to show a link to GoDaddy.com to register available names. It also has Google Adsense and GoDaddy banners enabled and configured to show them alternately. It has the option to look up single or multiple names. (opens in a new window)
Same configuration as the pro script above but with the addition of a CAPTCHA (opens in a new window).