The first J/psi -> mu(+)mu(-) signal in the ATLAS detector, from 7 TeV proton-proton collisions in the LHC, with integrated luminosity of 6.4 nb(-1) was extracted and analysed. The reconstructed invariant mass agrees with the PDG value within statistical uncertainties, whilst the peak width is compatible with Monte Carlo expectations. The kinematic properties of the J/psi candidates are presented. Two examples of future B-physics measurements are given. First, lifetime determinations are shown, in preparation for future high precision CPV measurements, second, the expected ATLAS sensitivity for rare decay B(s) -> mu(+)mu(-) is reported.