Artrage is described in this way:
ArtRage allows oil paints to smear and water colors to blend without the mess. The creative experience with ArtRage is recognized as the most realistic simulation of natural media effects that is easy to learn. ArtRage also works great with multi-touch screens for Windows and all Wacom pen tablets like Cintique, Intuous and Bamboo. In addition, Sony selected ArtRage as the creative software for its newly launched line of VAIO Windows 8 touch screen PCs.
At MacWorld SF, this Artrage demonstration shows you, in one viewing, how the software’s used to make art work on the Mac, and also on the iPad tablet. Given its capabilities, you might think it’s an expensive item of software, but it’s not – the retail is about $40 per copy for the basic version.
Try it for yourself. Visit: http://www.artrage.com/