NameQL - Fast and friendly way to find a usable name for your idea, app or business
Domainr - Domainr is the only ICANN-accredited domain status API provider.
Naminum - A company name generator that's actually useful
Lean Domain Search - Find a Great Domain Name w/ twitter handle availability
Naming Matters - A new, affordable naming startup for startups
Instant Domain Search - Search domain names instantly by showing results as you type.