www.majokoshoujo.net (now dead, there is a cached copy in google, tough) says that :
... Also, the Sega Saturn Game "Majokko Daisakusen" is due out on 2/4/99. OST CD of the Saturn Game: "Majokko Daisakusen - Natsukashi no Majokko Song" due out on 1/21/99 2600yen, COCX-30267 from Nippon Colombia.