I've been tied up lately with a lot of other things. (Hence the delay in getting new postings up).
One of those things is a paint program for the iPhone called Squiggles. The link above takes you to more info.
I frequently need to sketch little things to discuss with people on set or at a workstation. This also allows painting on photos so that useful for noting items. I have many more features in the work (along with others apps). Some these will probably be specific to visual effects so post a note for any feature requests to the existing app or to new apps you'd like to see.