My son has become very interested in GBC. What would be a good website to find starter level motors, blocks, etc.and kits for him to begin with. We hope to go to the Chantilly, VA show later this summer. Thank you
Not quite sure I understand what you're looking for. Are you trying to source the bricks themselves? In that case, there's nothing special about GBC in this regard - get your components from LEGO Shop@Home, or Bricklink, or eBay, or garage sales or wherever else you can.
The new crawler crane (42042) is a great parts pack to get started with, though it is on the expensive end of the 2015 range.
See also the Getting Started page on this site for hints on building your first module.
I will be one of the two coordinators at the Chantilly show this summer. Even if you do not feel as though your module is "finished", bring it. Introduce yourself and your son, we at the GBC area are always willing to help figure out a problem or fix it up right then and there. On top of that while the GBC is running there is much to be learned just by watching other modules fail.