I don't know if any of you watch the
photoshop guys , but they did a tutorial on making a stationary car look like it's moving. Unfortunately you can't download old episodes unless you're willing to shell out a couple of bucks, but the tutorial seemed simple enough (they always make it simple, but to get perfect effect you'll have to be a bit more detailed).
It's just a matter of selectively blurring layer masks..
select just the background of the photo, do a light motion blur, then select the tires and do a radial blur.
I'm not denying that the shot might not have had any post-processing, but I figured since this is the post-processing forum, it might be nice to show how I would do it..