While poking around YouTube I came across two good examples of bipedal robot walkers using the LEGO NXT on MoveToDecaf's YouTube Channel.
The first video is of a biped robot named Little Joe:
The second video is of an un-named walker using the rocking motion of the controller for movement:
This is definitely inspiring me to get off my duff and start making more progress with my LEGO NXT system. I am don't think I will build a walker, but I hope to post a video of a rover of mine on this blog some day.
Cheers ~ Jim