It's very difficult to get into any of the UCs if you're OOS. It's hard enough getting in even as a resident! I don't remember the exact numbers, but they're very low. Check out the MSAR.
ucsd will be tough, although they do interview a fair amount of out-of-staters. the problem, though, i think is that they don't accept many of those people. ucsf and ucla are definitely much more feasible for out-of-staters.