I recently picked up one of these at my local auto shop and have found it to phenomenal for the wheels:
http://www.peakauto.com/products/car...leaning-glove/
It's a full "glove" style microfiber wash mitt. It allows me full range of motion with my fingers. I can just wrap my hand easily around each spoke and scrub it (including the back) and it allows me to use a single finger to get into that groove that goes around the entire rim. I can also get a finger in between my lug nuts and the wheel in that area for a good clean. My wheels are now washed in less time and I get them more clean. I'm happy, especially for the $7 or $8 the mitt cost me.
And although this is slightly off-topic: I started using P21S when I got my 1LE and after I finished a bottle I switched over to Sonax ... never going back. Sonax does a significantly better job, it is worth the money to me.