I grew up in India where people tend to eat a LOT of lentils, and I cook dals of various kinds at home all the time now. I definitely recommend a pressure cooker. It'll cook everything much faster, and you needn't pre-soak most dals at all. You can get one at an Indian store for about 20$, I think. When mine wasn't working briefly, I tried boiling dal in a normal pot, and couldn't believe how long it took!

As for black beans, kidney beans, and black lentils (used to make dal makhani) I do usually pre-soak them overnight, but if I forget, or am feeling spontaneous, I use the quick soak method: boil water, soak beans for 1 hour, then cook in the pressure cooker. It works fairly well. I learnt of this from Martha Stewart ;)