Cabs cost $2.10, plus $1.80-$2.30 per mile. They are plentiful during the day downtown -- especially along Broad Street and near major hotels and train stations. At night and outside Center City, taxis are scarce. Your best bet is to go to a hotel and have the doorman hail a taxi for you. Or, you can call for a cab, but they frequently show up late and occasionally never arrive. Be persistent: calling back if the cab is late will often yield results. The standard tip for cabdrivers is about 15% of the total fare.
Olde City Taxi (215/338-0838). Quaker City Cab (215/728-8000). Yellow Cab (215/333-3333).