The controlled and coherent manipulation of individual quantum systems is fundamental for the development of quantum information processing. The nitrogen-vacancy (NV) color center in diamond is a promising system since its photoluminescence is perfectly stable at room temperature and its electron spin can be optically read out at the individual level. We review here the experiments currently realized in our laboratory concerning the use of a single NV color center as the single photon source and the coherent magnetic manipulation of the electron spin associated with a single NV color center. Furthermore, we demonstrate a nanoscopy experiment based on the saturation absorption effect, which allows to optically pin-point a single NV color center at sub-λ resolution. This offers the possibility to independently address two or multiple magnetically coupled single NV color centers, which is a necessary step towards the realization of a diamond-based quantum computer.