Take a Taxi USA
   Listing of taxi services in US cities. Also offering a wireless version of the site for web-enabled phones and PDAs.
   http://www.takeataxiUSA.com

Taxi Direct
   Online directory of Taxicab drivers and companies.
   http://www.taxidirect.com/

Taxi Drivers of America
   Taxicab driver discussion group on Yahoo.
   http://groups.yahoo.com/group/taxidriversofamerica/