I really liked the tool. It's very helpful for making animations, however, before I start using it for my projects, I would like to know if I'm allowed to use it for commercial projects?
Paint of Persia is a rotoscoping pixel-art tool · By
Of course. Desert Child use it for example.
What you create with the tool is your property. Just be careful about the references you use, which may be copyrighted.
(and the tool itself is under GNU license 3)