DirectSong

DirectSong is a premium music service that sells extra audio content for Guild Wars.

Their current wares are:
 * Guild Wars Special Edition Soundtrack (Four additional tracks came free with the Guild Wars Special Edition)
 * Battle Pak 1
 * Sorrow's Furnace Mini-Pak (Free)

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 with a bitrate of 128KB/s.