According to an article in The Korea Times last week, the audience for mobile TV in S. Korea has reached 22 million. While this sounds like good news for SK Telecom, KT and LG Telecom, the article said "Despite the growing audience, however, a sustainable business model remains elusive for television operators who are reeling from declining average revenue per user and weak advertisement sales."
It is important to note that the Mobile DTV referred to in The Korea Times article is DMB (Digital Multimedia Broadcasting) and it is offered over satellite to mobile handsets by TU Media, a division of SK Telecom and over terrestrial transmitters by SK Telecom, KT and LG Telecom. Although South Korea adopted the ATSC standard for terrestrial DTV, as far as I know mobile DTV based on the ATSC mobile DTV candidate standard is not yet available.
Terrestrial DMB is a free service and some of the satellite channels are free. The mobile carriers sell handsets with both terrestrial and satellite DMB capability.
South Korea takes to mobile TV like crazy, says TNS Global
Pioneering DMB, nearly half of the country's population enjoys mobile TV