Do you mean this one, MrKite?
http://en.wikipedia.org/wiki/Mega_Man_(TV_series)
There have been a couple of Mega Man cartoons, but that's the only one I watched. Well, aside from Captain N, but I barely remember Mega Man's role in that. Anyway, this cartoon was pretty good. I enjoyed it at the time, but I don't think it aged very well. I found an old video recording of an episode a couple of years ago; it wasn't as good as I remembered it being.