I used an app called, "Sketch Guru" by Bejoy Mobile.
Only problem I have with it is, sometimes it crashes and doesn't save your drawings as you want it, or you just have a hard time trying to start another one because its a bit buggy at times when it decides to crash.

I do like however how it records the strokes you did and when you're done with the drawing you can actually see the strokes that you used to create it. Pretty neat app I found for the kindle on the Amazon store.