i use a couple things for my wheels. for getting my tires to shine, i use Black Magic Tire Wet Foam. it's really easy to put on, doesn't require any wiping, cleaning, etc.
for cleaning up the wheels from dirt or brake dust, i use simple green, the same stuff i use to clean my engine. i've never seen a degreaser/cleaner work as good as simple green, and it's complete safe and cleans up easy as well.
i usually do my engine and wheels at the same time, bring it right to the do it yourself car wash. since i show my car often during the warmer months, i do this process once a month.
for the first time doing this, you might want to take a cloth to get off and dirt or grime that may have built up over the years (depending on how old your car is and your environment, of course).
after that, simple green the engine and wheels, and let it sit for 5 mins. blast the simple green off with the pressure washer, then respray the simple green. wash it off again with the pressure washer, and then foam the tires. it will look better than new!!!