Via Lifehacker, although I don’t have the article link:
You can search for residential or business phone numbers using Google. Enter a search like:
rphonebook: Donald E. Duck, Cambridge, MA
for residences or:
bphonebook: starbucks, boston, ma
The “bphonebook” version looks just like a normal text search (I’m not sure if it’s actually different), but clearly the “rphonebook” is.