I don't use it myself, and honestly, it has not gotten much use by anyone else. DD really enjoyed it for the week before the stylus disappeared, but she didn't ask for it to be replaced, either. That said, neither she nor anyone else in our family is a dedicated artist.

Google for "flipnotes for PC" comes up with these as PC analogs:
http://animation.about.com/od/referencematerials/a/freesoftware.htm