Domain After Market?

How do companies get the "expiring soon", "deleted", etc domain lists and start their domain site where visitors can purchase such domains? Companies such as afternic.com and deleteddomains.com do this. How can I get such lists to start my own company?

you have to amke a corporate relationship to other websites where domains are parked for revenue or sell/bidding.

You can make your own list and contact the owners to add their domains in the list of sell.

Further you can park your own domains at revenue direct, without any cost. They will sell your domains as well as monetize the domains to earn some revenue.

revenuedirect.com for adding domains and http://www.domainsearch.com/cgi-bin/Domain_Search to search sold domains.