I dunno how many people know of this program already, but I just found out about it and thought I'd share. It's free (you can make a paypal donation if you want)
as to how it works, it lets you paint with natural mediums: oil paint, crayons, chalk, pencils like Painter does. The interface reminds me more of Alias' Sketchbook - but anyways. I like it. Give it a shot why don't you?