Go to a drive-in car wash, feed the machine quarters until it turns on, and use the high-pressure hose to rinse it off. That works most of the time, especially if you get nice and close. I follow up by pressing the tire cleaner button, and then a regular wash and spray-on wax.
I have the stock plastic wheel covers, though. If you have rims, you may want/need something to keep them shiny.
(Also, while we're on the subject, stop by your local auto parts store and spend four bucks (Advance) on some spray-on-let-dry tire cleaner. Doesn't do much for brake dust, but keeps your tires looking shiny.)
2007 Pontiac G5
1999 Pontiac Grand Prix GT - Stock engine ate transmission.
1997 Pontiac Bonneville SE - Cammed engine ate transmission.