Hi, Matt. It is very possible to paint aluminum siding. I have done mine twice now, just for the color change. Thankfully, all I have to do is gable ends and eaves but it should not make a difference.
One big concern is chalking. If your house is chalking heavily, you may have to pressure wash. No sense painting on a surface that is already coming off. My other tips are real easy. Find a good, local, independent paint store like a Benj. Moore or Sherwin-Williams dealer (or check the board for JayJ's favorite that may be in your and his area but is nowhere else in the world. Don't even think about using Sears paint. It is flaking off my wood and returning a foot long flake for exam, they said that it was my problem. That's twice with Sears. Two strikes on Sears paint and they are out--for me.
Weather is real important. You want it dry and not in hot, direct sun for your and the paints sake. Talk to your dealer about how much and what prep to do. It varies more outside than in. And it also varies with local conditions.