Source: http://lifehacker.com/5609478/deviantart-muro-is-an-html5-drawing-app-that-works-on-your-ipad
The application works well in any HTML5-compatible browser, which is basically all of them except for Internet Explorer—though it's obviously a lot easier to use if you've got a drawing tablet as well. The application also works surprisingly well on your iPad—the touch screen is an ideal platform for a drawing application. There's a good set of drawing tools, and a whole slew of filters for blurring, sharpening, embossing, or any other image editing type of task once you're done with your image. It's a great tool worth a look, if for no other reason than to see what HTML5 is capable of.