Hellas mentioned DomainsBot in another thread and it's cool enough that I thought I would highlight it here.
Their algorithm looks to be quite good at finding domain names.
The Advanced Search feature is exceptionally nice. Here are the available options:
- Extension: .com / .net / .org / .info / .biz / .us
- Status: Available / For sale / Expiring
- Include: Hyphens / Numbers / Related / Compound / Variation / Adult terms
- Max keywords
- Max Domain Length
I set it to show me only available (i.e. unregistered) domain names with .com/.net/.org extensions, and without hyphens or numbers.
I am now looking through a long list of potential domain names.