DirectSong

DirectSong is a premium music service that sells extra audio content for Guild Wars. When DirectSong music is playing in the game, the Direct Song icon in the Options panel will light up.

Their current offerings (for Guild Wars) are:
 * Guild Wars Special Edition Soundtrack (320 kb/s)
 * Battle Pak 1 (320 kb/s)
 * Sorrow's Furnace Mini-Pak (free) (128 kb/s)
 * Guild Wars Factions Soundtrack (320 kb/s)
 * Guild Wars Factions Collector's Edition Expansion Music (exclusive) (128 kb/s)
 * Guild Wars Nightfall Soundtrack (320 kb/s)
 * Guild Wars Nightfall Collector's Edition Bonus Music (exclusive) (128 kb/s)

When the Sorrow's Furnace update came out, the associated music was only available via DirectSong, though it was offered for free.

DirectSong's music is only available as protected (through DRM) WMA files.