I'm not sure if you can use Steam, but that's where they sell it. I'm not sure if there was ever an official DVD release. When I was back in Ukraine last summer, though, you could find a pirated copy in just about any games store. And the game's not so old as to disappear from torrents already.
As for the VA, judge for yourself:
http://www.youtube.com/watch?v=3dqprJPwfk0
http://www.youtube.com/watch?v=r1DNlg4YZaE
It's not just the dialogue, it's even the battle sounds and, if you understand Japanese the translation itself. Especially compare the voice of Duke Hermeien (the guy in a checkered outfit at 1:45).
Also guess what, there's actually a demo:
http://www.gamershell.com/download_40086.shtml