Installing:
Simply place mere the data folder with Skyrims by dragging and dropping the entire folder to Skyrim's Root Directory

Or use a mod sorting software(Nexus Mod Manager, Mod Organizer, Wyre Bash etc.) to install the mod for you. No .esps/.esms/.bsas, no activation necessary.

Uninstalling:
Delete the "mus_maintheme.xwm" from the "Data/Music/Special" folder. Or uninstall with your favorite mod manager.

Compatiblity:
Will conflict only with other mods changing the Skyrim Maim Theme. No hard edits have been done, so no .esp/.esm is required.

Credits;
http://www.newgrounds.com/audio/listen/475943 - Download Source
http://floatingpointmusic.newgrounds.com/ - Author