I always soak beans because I don't like having to steam up the kitchen or leave them cooking for a long time.
this question has a great table for soaking times.
It seems like salt or no salt really only has to do with your personal preference, but I never do it because you can always add salt after, but you can never take it away.
Because I never sort through beans before soaking them, I pour out the soaking water out, but I always cook the beans in just enought water that there isn't any extra to be tossed (e.g. if I am making refried beans, add such that there will only be an extra 1/2 C or so).