Many PSX games have wonderful music, such as the Resident Evil series, Soul Blade,
Tekken, Metal Gear etc. However, not all of these games have their music files in cda
format, which means that you can't listen to them in your home stereo. In fact, most
games of this kind have one big game file, which I guess contains everything...
Does anyone know if there is a way to extract music from these large game files? I
suppose this is not very easy, given that every game developer can have their own
music (or sound) format, so one would probably need to have the same tools that they
have, but anyway... has anybody heard of a way to do it?

you can try the proggies in this url. used PsxMC successfully to convert music files in Bust A Grove last time.

http://www.ngemu.com/psx/tools.php?page=movies

I downloaded some of the tools from the site you recommended, but
apparently they all need a component called wnaspi32.dll in order to work.
Do you know where I can find it?

ftp://ftp6.nero.com/wnaspi32.dll ??

Has anyone ripped the music from Castlevania:SOTN for psx using any of these progs? I just downloaded some VERY poorly made mp3s of this musical masterpiece and am pretty ticked off. I'd love to encode a few mpc's off of my game cd if possible