Ok, it shouldn't be too complicated.
First, install the K&K Music Mod (download it from FileFront since the Repository is currently down).
Copy music.txt from Mount&Blade/Data/ and paste it to Mount&Blade/Modules/Native/ (or to Mount&Blade/Modules/YourMod/ if you want to play the music with a specific mod). You should make a back up of music.txt in Native first if you want to revert to the original music.
Cut the new .mp3 files from Mount&Blade/music/ and paste them to Mount&Blade/Modules/Native/Music/ (or Mount&Blade/Modules/YourMod/Music/).
Uninstall the K&K Music Mod with the uninstaller, which is in Mount&Blade/Modules/Music Mod/.
Launch the game with Native or the mod you pasted the files to.
That should work, I tried it.
fisheye said:
Where are these other music mods that you speak of? Linky please!
http://forums.taleworlds.com/index.php/topic,11220.0.html
I don't think there is a downloadable Knights of Honor Music Mod, it's probably copyrighted.