  We show how the weak field magneto-conductance can be used as a tool to
characterize epitaxial graphene samples grown from the C or the Si face of
Silicon Carbide, with mobilities ranging from 120 to 12000 cm^2/(V.s).
Depending on the growth conditions, we observe anti-localization and/or
localization which can be understood in term of weak-localization related to
quantum interferences. The inferred characteristic diffusion lengths are in
agreement with the scanning tunneling microscopy and the theoretical model
which describe the "pure" mono-layer and bilayer of graphene [MacCann et al,.
Phys. Rev. Lett. 97, 146805 (2006)].
