Instant Username Search - Check out if your username is available
Brandroot - Great Names for Great Ideas
Namechk - See if your username is available on 100+ social networks
BrandBucket - The original marketplace for business names and creative domain names.
Zlipa - Startup names with available dotcoms and logos
NameMing - Get smart domain name suggestions using synonyms, suffixes, prefixes, short url, new gtlds to find the perfect domain name. Generate ideas for social user names and check availability for free!