I don't know about using iso's but Grayface's unofficial MM8 patch allows you to make the game recognise MP3 files for ingame music.
You can get the patch
here. It also fixes alot of bugs and adds some useful features - you can find a list of changes in the thread I linked.
-- Now, if you have the patch, here's how to get music ingame:
Once you've installed it, start up the game once so that the MM8.ini file is created. From there you can edit some options specific to the patch. Close the game and open the MM8.ini file with a text editor. Make sure "PlayMP3" is set to 1. Don't change anything else for now.
Now, rip the music off your MM8 cd into MP3 files (Windows Media Player should do for this). Next create a music folder in the game directory and paste the music files in there.
Lastly, you need to rename the mp3's. The first one should be called "2.mp3" and the last one "16.mp3", corresponding to the order in which they are played from the cd when you don't have shuffle on (you should be able to just look at the order they appear in in the "now playing" list). Be sure to skip "1.mp3". It's not used.
-- Hope this helped!
You'd think Darkmoor was a ghost town, but instead there's plenty of life among the dead.
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