Hi Sean,It is really going to depend on the type of jousting that you are wanting to do.
There is the "hardcore" type as run by the WCJA - which you can see at www.happyproductions.ca
Or there is a more historical type as espoused by the International Jousting Association (www.worldjousting.com).
If you are interested in the first, go to www.wcja.ca and you can get their full info there.
If the later, you can see the armour regulations on the site I mentioned above. For the IJA the East Coast USA Director is Michael Carrol and he can be reached through his website: http://www.redshield-1391.org/
If you have any specific questions, give me a yell and I will help you out as much as I can.
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Break a Lance,
Lloyd Clark
IJA Level 4 Jousting Instructor
Schola St. George Equestrian Combat Instructor
http://www.historiccamelot.org