  The B^0_s -> K^+K^- decay is the U-spin partner of B^0_d -> pi^+\pi^- and
allows a determination of the angle gamma of the unitarity triangle of the
Cabibbo-Kobayashi-Maskawa matrix. Using updated information on the branching
ratio and the relevant hadronic form factors, we discuss the picture that
emerges for gamma from the currently available data, which is in good agreement
with the fits of the unitarity triangle. We point out that the B^0_s -> K^+K^-
decay also offers interesting probes to search for new physics in B^0_s-\bar
B^0_s mixing, thereby complementing the well-known B^0_s -> J/psi phi analyses.
The relevant observables are the effective lifetime of this channel and its
mixing-induced CP asymmetry. We calculate correlations between these quantities
and the CP-violating B^0_s-\bar B^0_s mixing phase, which serve as target
regions for improved measurements at the Tevatron and the early data taking at
the LHCb experiment. Finally, we discuss the expected situation for the optimal
determination of gamma at LHCb, exploiting precise measurements of the CP
violation in B^0_s -> K^+K^-.
