I've been using my iPad as a sketchbook for the past few months, and I love it. I use a Pogo Sketch Stylus, which is a sort of pseudo-pen with a spongy tip. You can just use the tip of your finger to draw on the iPad, but I like the feel of something pen-like in my hand. I use the Autodesk Sketchbook Pro app for the iPad, which has layers, transparency, brush sizes, etc.
Business Insider mentioned me today in their article about ways people use their iPads to create content. They included my sketch above, which I did at the cottage recently. I drew this picture of my friend reading on his iPad using MY iPad. :-)
Any other illustrators out there with iPads?
For those interested, I tweet about digital publishing, e-books, impact on technology on publishing (esp. kidlit) & iPads at @ipadgirl.