A simple but lovely natural media painting and sketching program. Art oriented, but capable of loading/saving photoshop files.
Draft is a straightforward sketch app for iPad. You can get it in the App Store for $9.99.
It only comes in black. You can draw in white or red.
It automatically saves whatever you draw.
You can share sketches via email or Campfire.
See, there it is in Campfire. That too.