Eto Rangers had one opening song and 2 ending songs. The opening was "Mada Mada Mada," and the endings were "Aitakute" and "Seiza no Yane no Shita de." The background music is a fun way to bring a piece of the show with you even when you cannot watch it. I especially like the theme that plays when the Rangers are leaving Kirinda for a Novel World, but of course I also love the Nyanma and Aurahime themes. ^_^ The character image songs are a way to bring a bit of the cast with you as well. Yes, Nyanma sings on the Hit Songs Collection. So does Aura hime and even Kirinda. You can buy the CDs used in Japan or go hunting for mp3s on WinMX, Winny, and Share.
During Eto Ranger's time, 2 soundtrack CDs and 3 singles were released under the Nippon Columbia label. The 2 main CDs were for background music (Collection of Music) and image songs (Hit Songs Collection) plus the opening and ending songs, and each mini-CD single was devoted to the opening or one of the two ending themes. The singles also had karaoke versions of their featured song, as well as b-side "coupled with" (C/W) songs not seen in the CDs. Also the main CDs were released on cassette tapes.