Well done, Andrew. :-)

From my speaking experience*, audiences vary in their knowledge of, and attitudes to, Wikipedia. You'll probably need to cover some of the basics - i.e. how it works - but balance this with an educator's perspective: what good is Wikipedia for my students, or for me; why should they or I use it; how would they know if it's reliable or not?

The angle that I usually stress is that Wikipedia's transparent and participative nature has profound implications for the construction of knowledge, and becoming critical - educators trying to promote critical thinking have a valuable resource in Wikipedia to show students how knowledge is always contestable (and is contested!). (Some more at: <http://en.wikiversity.org/wiki/Inside_Wikipedia>.) And for those who just want the (unvandalised) facts, you could mention flagged revisions as a mechanism for ameliorating vandalism, and promoting reliability - as well as the fact that dealing with vandalism is an extraordinary, distributed effort, often using pretty sophisticated tools, as well as basic ones like recent changes, history, watchlists, diffs, rollback (ie 'how it works').

Also, don't forget Wikipedia's sister projects - Wikibooks and Wikiversity being the most obviously relevant ones. Teachers can write their own textbooks or materials, or adapt those of others - the practice of teaching has always involved sharing ideas amongst teachers. And students can give feedback on resources, edit them directly, or create their own resources that facilitate their learning processes, or simply document how they learnt. One thing that educators often feel strange about is that someone else could edit *their* educational resources - you can mention the ability to 'fork' into derivative works, rather than necessarily edit the same resource. These are cultural issues, and quite complex - but it's worth at least helping people recognise the opportunities, as opposed to the threats of free culture. This is a growing educational agenda now - taking the initiative of 'open source' towards developing 'open educational resources' (OER) - and Graham Attwell, who I've met, will no doubt be plugging this.

And yes, as Thomas points out, there are school-friendly Wikipedia resources - and that we're always looking for ways of improving/extending/refocusing them, and always appreciate help. ;-)

All the best,

Cormac

* Yup, will put my details on the wmuk speaker page now. :-)