As the trend gains steam over time, there's some official soundtracks which are being released as online-only, from various download services.

Here's some new Telenet OSTs through the Japanese EGG Music Service:
http://www.amusement-center.com/project … index.html

Valis 1 Fantasm Soldier PC-Engine Soundtracks [1-29-2007] 11 Tracks, 1260 Yen
Valis 2 PC-Engine Soundtracks [1-29-2007] 12 Tracks, 1260 Yen
Valis 3 PC-Engine Soundtracks [1-29-2007] 12 Tracks, 1260 Yen
Valis 4 PC-Engine Soundtracks [1-29-2007] 10 Tracks, 1260 Yen
Phalanx Original Soundtracks [9-14-2006] 48 Tracks, 2205 Yen

The Zoom SoundTeam has a bunch of OSTs up too:

Genocide, Lagoon, Phalanx, Genocide 2, Overtake Vols 1+2, Genocide Square Vols 1+2
http://www.amusement-center.com/project … index.html

Even individual composers have exclusive tracks offered on the EGG Music Service...

Noriyuki Iwadare has 5 songs up here [11-21-2006], apparently written for a project with the HAY Dance Company:
http://www.amusement-center.com/project … index.html

Shinichi Sakamoto has an Aquario Original Soundtrack [10-27-2006] 18 Tracks:
http://www.amusement-center.com/project … index.html

At least we get something on the USA side, there's stuff on iTunes from Square-Enix, such as these:

Square-Enix Official Bootleg Vol.1 [6 Tracks for $3.99]
http://na.square-enix.com/music/tunes/bootleg/

Although the S-E Official Bootleg Vol.2 is only on the JP iTunes. [4 Tracks for 600 Yen]
http://www.square-enix.co.jp/music/sem/page/dl/bootleg/

Best of Chocobo and the Magic Picture Book [10 Tracks]

I'm sure there are many more than these out there, so please add on here any that you might come across, so that they don't slip under the radar of those who might want to obtain them.

Don't know if this counts as it's been released as a preorder bonus (or something) before, but since they tend to be a pain in the ass to get, download option makes things a bit easier. If you don't mind settling with non-physical property when there *is* the real thing as well, that is. Anyway, Falcom offers Gurumin OST for download at listen.jp for 2520 yen, or 105 yen per track of which there are a total of 42.

The same page has links to a couple out-of-print Falcom albums like Special Box '91 (disc 3 only) and Perfect Collection Ys IV Vol. 1. Might be worth checking out if it's just the music you're after and you prefer legitimate files.

Could someone tell me if Akihito Ohkawa composed any of these soundtracks?

Valis II and III PCE music is amazing.  I have the two pressed Valis OSTs, which are nice but not on the same level.  Someone needs to just press some of these CDs up and sell them for 2000 yen.  Or I suppose I could get around to actually ripping the redbook.

Here are a bunch of US soundtracks, most notably Oblivion and a complete Morrowind OST, all in DRM-ed WMAs. Oh joy. At least you can burn them to a CD and seems they include cover art.

http://www.directsong.com/