Current and Future Limits on General Flavour Violation in b-->s Transitions in Minimal Supersymmetry

We discuss the current and prospective limits that can be placed on supersymmetric contributions to $b\to s$ transitions in the Minimal Supersymmetric Standard Model with general flavour mixing amongst the squarks. We consider three processes: $\bar{B}\to X_s\gamma$, $\bar{B}_s\mu^+\mu^-$ and $\bar{B}_s-B_s$ mixing, and pay particular attention to the large $\tan\beta$ regime and beyond leading order contributions where the difference between our analysis and previous analyses is most pronounced. We find that even present limits on BR$(\bar{B}_s\mu^+\mu^-)$ and $\Delta m_{B_s}$ often provide additional constraints on the amount of flavour violation still allowed by BR$(\bar{B}\to X_s\gamma)$. Limits on supersymmetric and Higgs mass parameters can also be strongly dependent on the flavour violation. In particular, the case $\mu<0$ can still be allowed, even for light sparticle masses. We discuss how future measurements at the Tevatron, the LHC and elsewhere can improve present limits but also provide unique signatures for the existence of flavour violation.