Splines and orientation

Can anyone help or point me to a good site…

I have a 3d Spline line from which I wish to animate an object (for example an aeroplane), problem is as I traverse along the spline how do i rotate the plane so it is always pointing ‘forwards’ (in the direction it is travelling). Im not too worried at this moment about banking the plane when it turns.

Hope you can help…

David