Since 1 may 2009, Seoul Metropolitan Government got start service for a foreigner , It call as Seoul International Taxi.
Seoul Metropolitan Government selected 127 taxi drivers who are conversant on English or Japanese for the International Taxi, also still announce for driver.
I have checked announcement, It has interview of English or Japanese and have to take course to be International Taxi Driver.
International Taxi fare is a little bit high position than a normal taxi, but I think It will be useful for foreigner.
If you want use International Taxi, you got to reserve.
Call Nm 1644-2255.