I will leave this post stickied and edit it as I learn of more clubs. If you know of any or are part of one, post it in here and I will edit the first post. If you don't see a club that you know of please post it.

Ontario:
Trillium Miata Club (GTA) - http://www.trilliummiata.ca/
London Miata Club - http://londonmiataclub.ca/
Underground Miata Network (Ottawa) - http://ottawamiata.net/
Simply Miata (GTA) - http://www.simplymiata.com/

Quebec:
Club Quebec Miata - http://www.quebecmiata.com/site/main.html
Club Miata du Grand Montreal - http://www.cmgm2003.com/

Alberta:
Wild Rose Miata Club (Edmonton) - http://www.wildrosemiata.com/