Welcome Red! I hope you enjoy your stay.
C.com has a Costume Discussion: Props and Accessories sub Forum. At that top of that should be a "Tutorial List." It has links to many prop Tutorials. The best you can find IMO would be Featherweight's Tutorials. He can make almost anything out of cardboard and he happily posted his tutorials on C.com for all to use. I'm sure you'll find 'em most useful!
The Lunatic Bowgunner,
Khezu Z Armor (Monster Hunter Freedom Unite)
Megacon or Metrocon... decisions, decisions.