If you have a Color Me Mine nearby, check them out as well. They have everything you need; tiles, paints, and they'll even finish the tiles for you. I know you want to do this yourself, so maybe you can just check out the supplies, the type of paint, whether the tiles are glossy, or matte, etc.

I do this with my grandson (age 4). Last year we took some watercolors and painted large sheets of paper (11 x 17). While it was still wet he jumped into the middle of the wet paper with bare feet, then bent down and added his hands. When we framed these they made the greatest gifts! Great Grandma got one for her birthday, Mom and Dad got one each for Mother's Day and Father's Day. I kept one for me, put one in the cedar chest for grandson when he grows up.

Another thing we did was take some clay, (actually, I like to use Fimo, which you can bake until hard), flatten it out, and press his hand into the center to make a little plaque.

We've decorated flower pots, planted flowers and plants, made sock puppets. We both love to do these things together. It's going to be a drag when he grows up and doesn't want to do it any more.