Everybody calls these "rolling shots" but the proper term is panning shot. nhhiep pretty much summed it up but also make sure to put the focus mode on servo. This allows focus to stay on the car as you move the camera while engaging the auto focus. Google "panning shot" and I'm sure you will find lots of pointers. Check this out, it's from a photography board that I'm a member of
http://photography-on-the.net/forum/...hlight=panning