Those would be said "There's no point in doing it." or "There's no point doing it.", and "It's no use doing it/that." And they would mean the same thing. "use" may be a little more all-inclusive about there being nothing gained in or reason to do something and "point" maybe referring to the situation at hand, but generally they can be interchangeable.

They basically mean the same thing. However, I believe it would be more common to say "THERE is no use (or no point) in doing it."