Tutorial: Still to Motion
A simple way to make you car look like it's moving.
       
 Still to Motion
 
Difficulty - ***
The car you want to set in motion really should have a driver in it! If not it looks rather stupid.  
Now, zoom in on one wheel and use the lasso tool (L) and slowly go around it.  

Then head for Filter>Blur>Radial Blur.

It'll need to be on the "spin" setting and you'll have to adjust the amount by how fast you want the car to be going.

I set mine at about 40.

Then repeat the same steps for the rear wheel.

 

Now then. The rims are moving.. but the car isn't?? Don't you worry, we can sort that.  

Use the lasso tool (L) and select the area as shown.

Then hit Ctrl+Shift+I... this inverses the selection.

Then go to Filter>Blur>Motion Blur. From this, you can figure out how to do it yourself!! You can adjust the intensity of the filter (IE: how fast the cars going) and the angle.

 

Its moving! But.. wait! the bits in the windows aren't! Not to worry my good friends, follow the same steps above on each of the portions of the window (ensuring its the same intensity and angle)..  

That's it, we are complete!