We have produced an efficient parallel program running on the DECmpp which performs simulated tempering on Ising spin models. However for this program to run effectively, especially for near zero temperature for optimization problems, we need to be able to tune the variable parameters in the tempering algorithm. These parameters are the temperature changes, and the constants which can be added to the energy at each temperature. Estimates for these quantities can be obtained if the energies are known, however to get reasonable acceptance rates for the Monte Carlo update on the temperature, these variables will need to be fine tuned, probably by some dynamical procedure. Good methods of tuning these variables to obtain good acceptances will need to be found before simulated tempering can be as effective as simulated annealing for general optimization problems.