If SLT number, there was a post sometimes back about a reverse SLT directory. I have not tried it. Search the forums and see.
Other telecos, I dunno if there are such directories available.
Most telecos will not give owners name and address to other people. But if police ask for investigation they will give details to police. Some situations it may need court order.
Some telecos, just give number and pay money some small amount like settling bill or ask how much outstanding. If cashier asks Mr. X, you 'may' get away by saying yes. Some cashiers wont ask name just take money for number and give you receipt. Receipt for payment will have name of registered owner . Try with your own number or friends number first. Of course this way you will only get his correct name.