T-rad wrote: I actually think Cerat would be the best person to ask, as far as I know he used to speak at schools before. I've never done anything like that, so it would be better if you got a guy with some experience.
Unfortunately I have to work for a living now.

Trust me, for those age groups, you don't have to be an expert.
I would recommend that you take more than one person, cause a bunch of kids storming a table can get nerve wracking when your spiders are sitting there. 3 people would be ideal.
Take a few big spiders and just talk general crap about them. Just basic things like they have 2 body parts, 8 legs, explain silk uses, venom, mating for the older kids. Most of the kids will just be impressed with the size of the tarantulas and not really focus on what you are saying most of the time. If possible, something that you could handle and possibly let a kid or 2 handle as well. I used to use my darlingi female as she was an angel and when I got into tarantulas, I use to use a big male G.pulchripes to show and let kids hold or maybe a docile rosea.
Don't do the whole school at once. Snakes are much easier to handle and show off, but when the kid in the back row wants to see a 10cm spider and can't even see you, then they get bored easily. I use to do it a grade a time. Quick talk about 5 or 6 spiders that you bring with for about 20 min and then get them to ask you questions. Let the kids then come walk past the tanks and have a look at the spiders. If Dimitri could help with it, a quick slide show with some pretty spiders would also do the trick.
Any other questions?
You are welcome to drop me a mail as well if you need some pointers.