In response to your question on how to work with the kids, I'm sure that there are plenty of parents on this forum who have taught their own children basic skills, so they should also have plenty of suggestions.

I've taught kids (fine art and drama), and I've found that having activities that promote participation from your audience is a great way to get them interested and absorb the information, especially if they're little. Role-play and getting them to act out scenarios makes it more fun for them, and it's also kinda like practice. Really engage the kids in the presentation by getting them to raise their hands and answer questions. Children also tend to respond well to a cheery sense of humor.

If you have any friends who are cops or firemen or anyone in a snazzy uniform who can supplement your lecture, kids really dig that, too. (I did when I was little, but maybe that's why now I can't resist a man in uniform <img src="/images/graemlins/wink.gif" alt="" /> Sometimes hearing the serious stuff straight from a uniformed authority figure can make a deeper impact. Being honest about the reality of things might scare them a little, but then they are more likely to discuss it with their parents later. That's my experience from bringing in the cops to talk about strangers to the wee ones.

And be careful with packaging the whistles - if there is no packaging or plastic barrier, the young children unable to resist playing with the whistles may interrupt your lecture (if passed out beforehand), or drive the classroom teacher insane (if passed out afterwards).

Good luck and thanks for doing your community a favor.