I found this great site with all pieces of music from the manga. Here's the link:

KISS (Matsumoto Tomo) - Music from the manga

All credit goes to Mitari Enteh aka Jane and the respective artists.

UPDATE:
The original site shut down some time ago but thanks to the Wayback Machine the list is still accessible.

[color=#8A795D]"Stories are what death thinks he puts an end to.
He can't understand that they end in him, but they don't end with him."

• Ursula K. Le Guin, Gifts[/color]

To be savoured:

• Blood Alone by TAKANO Masayuki
• Otoyomegatari by MORI Kaoru
• Gangsta. by Kohske
• Seishun Kouryakuhon by AKIZUKI Sorata