I've been looking around lately and noticing a lot of people selling expired domain names, but where does this data come from? Is there a central database somewhere that these guys poll to see what's expiring when?
" you can search through the names that are "pending deletion" within a 7 day time frame"
Yeah, you can search. Only to discover that the minute your domain is released it is automatically reregistered by some who collect domain names. Unless it is some weird domain name. So be very very fast.
Actually you don't have to be a registrar to have access to the zone files... Verisign provides a program whereby they grant FTP access for free to qualified applicants. If you have a legitimate reason you can get access too. By running "comparisons" over the previous version of the zone file you can get a picture of which domain names are changing status, which ones are purged which ones are newly-registered etc. Also it is possible to register .com without providing DNS servers. Then these names will not be included in the zone files.