These textures were originally created for UFO:AI, they are based off the work of Lukas "Rastaman" Beyeler who released his textures under GPL2 as I am doing. The original skins and the models they are for are available from the UFO:AI project under GPL2 licencing.

All the .md2 model files and the original source textures are here:
http://ufoai.ninex.info/licenses/models/index.html

This head pack is designed to work with this armor Pack:

http://opengameart.org/content/modern-uniform-and-armor-textures-ufoai

This head texture pack contains a variety of soldier head textures, with a combination of race, facial hair and sunglasses to give units within a squad an individual appearance.