Painting metal, regardless of type, isn't that difficult. Surface preparation is the key. Lightly sand the metal surface to dull it. Next, give it a smooth and even layer (or two) of primer (most primers come in either grey or black), watching out that you don't allow the paint to run. After the primer is dry, you can literally paint it anything you want to. I would suggest at least two to three layers of paint for a nice, clean looking paint job.