It's simple. For the next four weeks, "net earnings" from WINtA will "directly benefit the Save the Children charity teams active in Japan, helping children affected by the devastating earthquake and tsunami in the country." You snag the app for free ($0) and the net amount that NanaOn-Sha receives from song purchases (that's minus Apple's 30%) will be distributed by OneBigGame to "directly support Save the Children in setting up a network of child friendly spaces for children in the worst affected areas of Japan."
How is this different than the usual relationship OneBigGame has with Save the Children? While normally OBG would redirect 80% of its earnings towards both Save the Children and Starlight Children's Foundation, "in light of the recent events in Japan, OneBigGame are proud to make a special case by re-routing donated funds generated by WINtA to support Save the Children's relief efforts in the affected regions, with immediate effect." Go, get your philanthropy on.