Is it too early? 
Last year I took my son trick or treating for the first time, although it was nice seeing him have fun - it's bloody cold and a bit tedious as some houses these days just don't do trick or treating, so you're hunting down the sweets!
I was thinking of doing a little party for him, with nephews and nieces, this year. We have done this before but he was 1! He's 3 now. I was going to make cakes and other Halloween themed food and I was going to make up a present bag for him of monster stuff and toys, DVDs etc. for him to unwrap. Too much?
Then I thought I wonder if there's somewhere that's doing something Halloween themed for kids? Like a ghost walk/hunt or something...
I don't know, what do you do?