SIMPLE GREEN!! It works great for cleaning, plus it is harmless to the brake pads. Spray it all over the wheels and wait a cpl minutes and you can almost rinse away the brake dust.
I also do not care for Armorall. It looks good for a day or two, but I've found that it dulls (like a bleaching effect) the tires over time. If you desire the wet shine look on your tires, Black Magic will work wonders. I personally like my tires "al natural".
Lastly, waxing your rims will protect them and allow you to wipe away brake dust with ease. I've known some to even wax their windows to this same end.