<p>I am trying to animate an object, let's say its a car. I want it go from point</p>

<p><em>x1,y1,z1</em></p>

<p>to point <em>x2,y2,z2</em> . It moves to those points, but it appears to be <em>drifting</em> rather than pointing in the direction of motion. So my question is: how can I solve this issue in my updateframe() event? Could you point me in the direction of some good resources?</p>

<p>Thanks.</p>

You need to work out the initial orientation of the car, and the final orientation of the car at its destination, then interpolate between them to determine the orientation in between for the current timestep.
This
article describes the mathematics behind doing the interpolation, as well as some other things to do with rotating objects that may be of use to you. gamasutra.com in general is an excellent resource for this sort of thing.