Domaintools provides a free option but the searches that can be done are limited so this could be disappointing since it won't be working all the time if you exceed the limit.
http://xml-api.domaintools.com/
Here are some paid versions that may interest you
http://www.bigwebmaster.com/1840.html
DigiDomain is an integrated domain lookup, name spinner and whois tool developed for ISPs and Domain Resellers who wish to provide easy domain search functionality to their customers, and link customers through to their order form automatically on finding an available domain. The new version includes a Shopping Card. Associate prices with Third Level Domain and add you hosting plans. Key features of DigiDomain are: Quick and easy to implement, no programming required; Search against multiple Top Level Domains; Add new TLDs as they emerge.
* Cost: $149.00
* Version: 2.2
* Platforms: Windows
http://www.digiappz.com/digidomain.asp?id=2
DIGIDOMAIN is an integrated domain lookup, name spinner and whois tool developed for ISPs and Domain Resellers who wish to provide easy domain search functionality to their customers, and link customers through to their order form automatically on finding an available domain. The new version includes a Shopping Card. Associate prices with Third Level Domain and add you hosting plans.
US $99 (was €149)
Euro €99 (was €149)
Includes 1 year of upgrades free !
DigiDomain has a nice visual presentation when compared to the other solution above.
Take a look and see what works best for your needs.
There not many options available as it seems.
Good luck Herb
