Using bob:
http://forums.epicgames.com/threads/813554-Footsteps-when-not-extending-UT
Traces:
http://udn.epicgames.com/Three/CollisionTechnicalGuide.html
Collision for Foot Placement:
http://forums.epicgames.com/threads/932156-Foot-placement-and-collision-cylinder-movement-interaction-question
