FREE - In Google Play
FREE - in Win Phone Store
Sorry if that has already been posted.
The arrows you can draw on the board are too fat and often its hard to distinguish them when there are many arrows on the same line or pointing to the same square. It would be nice if the arrows were skinnier.
Also it would be nice to be able to draw different colored arrows using modifier keys (ctrl, alt, shift, etc) along with right/left click.