If you need, I can write a simple script that will query a list of names and tell you whether they are available or not. You can run it straight from your website and output can be a text file or displayed to the screen.
Querying a LARGE list (>1000) of names might result in your IP being banned for a few days however.
Actually, if you use rs.internic.net as the whois server, you'll never get banned. It's good enough to find out if a domain is taken or not, but you don't get the whois and the IP ban problem.