The company behind Kessen and Romance of the Three Kingdoms will be supporting all three systems within this fiscal year.
According to GameSpot, Koei announced today during the Bloomberg Forum that it would have GameCube and Xbox games released before the end of this fiscal year (March 2002). Apparently they do intend to have at least one game ready for each system's launch as well. No word on what games we'll see for GameCube, but Koei has previously commented that they were working on some GC titles geared towards younger players.