Computer drawing surfaces?
I was looking at some Adobe products and noticed [at this page](http://www.adobe.com/products/dreamweaver.html?promoid=DTELX) the artist appears to be drawing on her computer screen directly, it appears to be a Mac. How is the artist doing this? Is she using a special type of screen hooked to a computer or is this a stand-alone computer? Is there any reference material available about devices like this?