Finally a tool that is able to create an icon with transparancy from a png image with transparancy. You shouldn't think it could be so hard for the others to include it as well, but, they don't, so Can Combine Icons is my choice.

And to the person who rated this as a one star because it didn't do exactly what you wanted. Get a grip, this tool does what it says and it does it well, it does not claim to have automatic perspective something.