See 'STV Videos' for a demonstration of me presenting using some of this material.  I used to hand out Craig Henschel's pamphlet with map and ballot (below) and follow it like a power point, but have other material for shorter/targeted presentations which I've begun to do more often.  Most of the visual aids that I use in presentations are in the file Electoral System ResultsOO9.ppt.  This power point file is best edited with Open Office (free!).  The Skytrainer (also made by Craig) is has a lot of great info, so it's one of the hand-outs I like to send people home with.  Be sure to have this material authorized by the appropriate person/group and include this in small print when you print it off! (at UBC we include "authorized by the AMS, registered sponsor, 604 822 2050").  If need be, contact me and I can help you with this.

There is some additional material, Including visual aids for 8.5 inch by 11 inch paper here.

Here's an analogy I find quite useful for explaining the idea behind STV:
The first thing you need to know about STV is that you put a '1' next to your favorite candidate, a '2' next to your next favorite candidate, and so on.  You can rank as many candidates as you like.  The system then tries to get you your first preference, but if it can't it will try to get you your second preference, and so on.  How it does this I like to explain with an analogy:

Suppose a gym teacher wants to divide a class of sixty students into six equal soccer teams of 10 players each.  The teacher asks "who wants to be team captain"?  Nine students raise their hands.  So the teacher says "everyone else, line up behind your favorite captain," and soon there are nine teams of all different sizes.  One of the captains is really popular and has 15 players on his team, so the teacher says "5 of you, go find your next favorite captain".  This team is now the right size and its captain is 'elected'.  There's another team with only two players including the captain, so the teacher goes over and encourages them both to find their next favorite captain.  This captain is eliminated.  This continues until you have six teams of 10 players, where everyone gets one of their favorite captains. 

This is pretty much how STV was discovered, and while modern STV rules have been refined somewhat to make them fairer and more robust, this is still the idea behind BC-STV.  If you're interested in the details of the counting, we can go over them if you wish.

This analogy is adapted from: http://www.eoni.org.uk/index/faqs/pr-stv-voting-system-faqs.htm#03

Editing this Material
The power point files are best edited with Open Office, the PDFs with In-Design - I can help you locate the In-Design files.