DomainRipper is a powerful Whois server lookup utility for Windows 95/98/NT/2000 that helps you keep track of domain names. It can also check the central Whois database periodically and notify you via email as soon as a domain becomes available.
Why is this needed? Anyone has the right to buy a domain name that has not already been bought or one that has expired, unfortunately companies responsible for maintaining the Whois databases, such as Network Solutions, can take months to delete expired domains from their systems. You will not be able to register an expired domain until it has been completely deleted. DomainRipper will periodically check these databases and send you an email as soon as the domain name is available.