This tutorial is showing how u can emit particle from biped. You can create very good motion with the help of biped and then with biped particle also move same way.

First create biped and give it some motion with the help of *.bip file or create by footstep mode. Create particle flow and change Position Icon to Position object, so that u can choose biped (all part of biped but not bip01).
Remove speed and add Delete operator, put particle life 1.Now change in birth operator and increase particle amount to 100000 or 200000 depending on your system.

this is the render output of this tutorial

High res video for this tutorial is here