In this paper, the issue of Eddy Current Non-Destructive Testing system exploiting Giant Magneto Resistive sensors is presented for inspection of Printed Circuit Board. We propose a wide view of the state-of-the-art into this interdisciplinary research field, following the chronological path of the major results achieved in recent years. Once the relevant background is depicted, some important patents concerning eddy current probe and, in general, integrated software/hardware Giant Magneto Resistive-based systems are introduced, with particular reference to some patents about crack detection in conducting materials. The advantages of the proposed models and some possible improvements are discussed. Then a final look to the possible developments is given.