I'm working with the creator of SoundHack, Tom Erbe, to figure it out, since his program plays the sounds really well. If you want a version, email me. Download at the bottom of this page. It allows you to choose a resource and save it. RivenSoundHack is public domain.
Source code is included in the download package.
The purpose of this program is to listen to the great music in Riven at any time on the computer. The music is stored in the .MHK files found in the Data directory on the hard drive where Riven has been installed. On the PC there doesn't sem to be any program capable of fudging the headers, but as soon as I get the headers working any Windows program will be able to play it. The 2nd developer release of RSH is now available. Unfortunately this release uses the Windows WFC windowing classes and is thus dependent on Windows.