How to get DID local numbers (IP Telephony)

[Сергей Харламов <mentax () bk ru>]

Hi there,

Can someone explain me how can I get an block of DID (Telephony numbers)? For example I need 200 numbers. Is that 
special organization or I must buy it somewhere? 
What the rule for USA (NY) about telephony providing ? Should I have a licence to sale ip telephony?

Thanks.