The game engine that I use (C4 Engine - it rocks) supports Horizon Maps (self shadowing normal maps) and I was curious on its advantage. I built a stone rock wall to test the technique and it’s really cool. Anyway, I’ve released my textures (Diffuse, normal, height) for free (just don’t resell them)! Since Blender and its community is so rad, here is my little thanks in the form of free stuff! xD
Youtube video in action: http://www.youtube.com/watch?v=87EQQlz9X5w&feature=player_embedded
Download at : http://www.filedropper.com/rock_1
C4 Engine post with more detailed discussion : http://www.terathon.com/forums/viewtopic.php?f=30&t=11188&p=101816