I made a homing missile for the fps tutorial. Just to see how easy it is.
It marks the point when the user shoots with a raycast, stores the target and relative point. Then keeps on rotating towards that point. Thus you can shoot at a big enemy which is moving and the missile will track that point you had your cross hair over when you shot the missile.
It works best if you make the homing missile have very little initial velocity and instead make it accelerate using a constant force relative force and drag to give it a maximum speed.
