I got the LookAt script to work when using the Goober model (make the head look at a certain object) but when applying the same thing to a 3DS Max Character Studio head bone (or any other bone) it doesn’t work.
Hi,
What kind of script are you using for it? I’ve had no issues with the biped character and the lookAt controller, but I use the Head Look Controller found here:
http://blogs.unity3d.com/2009/07/10/just-looking-around/
Be sure and try it out. 
Hope that helps.
And as always please offer more than “it doesn’t work”. What do you mean by that? Is it that the model looks in the wrong direction? Nothing happens at all? Your computer spontaneously plays music? Ok, that last one was tongue in cheek but you get the point.
My immediate guess is that it’s looking the “wrong” way from what you expect and that’s likely due to your model having a different axis orientation. LookAt points the model’s forward vector (positive z) at the object/position of interest. If your model has something other than positive-z as the “forward” direction then you might get “unexpected” results.