I am not much of an artist myself but love the Art Rage App for the iPad. The app is currently on sale for $2.99 (usually $6.99) in the App Store until June 26 and is amazing for those who wish to learn how to paint or draw.
It is about as close as you can get to the real thing and is great for beginners and pros alike. If you love art apps, this is one worth getting. Get it before the price goes back up again.