That's a touchy one. Domain Name registrars are a little leery of automated tools, since such things have been unleashed on their servers with punitive effect. Plus the primary users of automated registry inquiries are domain squatters. So web services are not something I'd expect to find as much of as for other similar activities. In fact, I believe that some registrars will even throttle requests, so even if you use an app like "wget" or "whois", you may only be permitted a limited number of inquiries within a given time period.
Customer surveys are for companies who didn't pay proper attention to begin with.
subject: Check domain name availability in a program or a script