Dear Geoff;
        Not sure why nobody has told you about the education site on Molluscs -
 http://manandmollusc.net/  - it doesn't have a lot of "bells and whistles" such
as video-streaming and such, but it DOES contain a lot of information
appropriate to all ages, from about grade 4 upwards to second-year university,
about molluscs - and TONS of links - to hundreds of malacological and
conchological sites.  I suggest including some of the GREAT photos of
nudibranchs (in the links section, under gastropod subcategories) available on
the web, for your presentation - just print them off.

From the Warm White North (got up to 5 C in Halifax yesterday!);
Ross.