IO540 - don't let DFC catch you flying NDB approaches on a GPS.. he'll have a field day!
Learning how to NDB track is also useful if you ever find yourself dependent on tracking towards/away from a VDF (like the almost defunct VDF approaches) because the theory is the same - i.e. bearing to beacon increasing - turn left; bearing to beacon decreasing -turn right; and the plus 10/minus 10 mantra works, too. Something which might save your life if you end up in IMC with no working nav kit but a serviceable radio. (Though obviously a radar approach would be preferable!)
Tim