The bi-annual Pro Walk Pro Bike is the premier conference for everything walking- and cycling-related in North America.

Even if you weren't able to attend the 2012 conference in Long Beach, CA (alas, I am among that group), you can check out videos of keynote presenters and powerpoints from breakout sessions here: http://www.pps.org/pwpb2012/presentations/

I haven't watched it yet but the rousing keynote by Mark Gorton that closed the conference was apparently quite popular:
video - http://www.pps.org/we-are-the-majority-the-cars-dont-vote/
presentation - http://rethinktheauto.org/national-presentation/

Note that the next PWPB conference takes place Sept 8-12, 2014, a little closer to home -- Pittsburgh.

cheers,
Beth