I am not sure about pencil on oher os's...

as for anime software, one very cool thing is you can make a drawing in one frame, copy it to a future frame, tweak it a bit, and the software calculates all the frames in between to take a ton of work out of the animation part.
Also, there is the option to scan in your own drawings.
And the other thing we've seen so far is that the software allows you to create a skeleton for any creatures you draw so you can control the animation this way...ds hasn't gotten into that part yet.