Yes I have.
Step 1 is to go into the playstation eye part of the options menu. Make sure your camera is suitably zoomed in and the acquisition box is set around where your head will be. Have a play with the settings and you should see the white cross follow your face around the box as you move. It will help the camera/software if the lighting is reasonably even on your face.
Step 2 go to arcade mode time trial and select a cockpit view. You should now be able to look around the cockpit.
The unbelievably frustrating and stupid thing is I think that it only appears to work in arcade mode time trials. Hopefully they will patch it to work in career soon as I bought an PS Eye mainly for this game and spend 99% of my time in GT in career A-Spec mode where thus far it doesn't work!