I find soaking does little to speed the cooking :-/. If the beans are reasonably fresh (which they *ought* to be at this time of year, with bean season about 3 months gone), they should be done in 4-6 hours. The older the beans, the longer they take to cook. Last time I had really fresh beans, each month of age seemed to add around a half hour to an hour of cooking time.

I should ask my boss where she'd go around here to get really fresh beans...