Here is the original photo, taken with a point and shoot camera (fit's in saddle bag)
Here you see the first modification to the photo, I used Photoshop CS3, I started by duplicating the first layer, than applying a motion blur to the direction of the rider. Then I erased the top layer to reveal all the blur from the filtered image below...It is quite easy.
Then this is the final image with touch ups and some vector brushed downloaded off the internet...
Try it out to make some cool photos, it's fun!
Photoshop CS3, Free alternative:Gimp