Ask HN: Where to find public business information?

I need information about all types of establishments in the US (restaurants, rock climbing, stores, etc), but I really just need the stuff that is officially registered (the address, the name, perhaps if possible the type of establishment).

Does anyone know of a government (or public) location to get this information digitally? Or is this sort of information copyrighted by services like yellow pages so you need to ask them to give it to you?

Basically has anyone done this sort of data mining before and is willing to share some details?