I'm sure I'm not the first person to find this out, but didn't see a thread and thought it was cool, so decided to post it.
HOW TO GET THE WOW MUSIC - FREE!
All you need is a copy of WoW installed and MyWarCraftStudio!
1. Open MWCS.
2. Open common.mpq
3. Open the folder in the filetree view that says "Sound"
4. Right Click the folder that says "Music" and choose "Extract Folder..."
5. Choose your location and click "Save", and you now have the WoW music on your computer!
Simple and easy! =D