Utility handover - how does this work?

I just purchased an investment condo unit in Park Slope, and I just recently rented it out. The question I have is, how do I find out who provides the electricity and gas for the unit? I assume its con-ed and national grid - lets assume that is the case, how does the utility accounts for the tenant get created? Do they call and set this up by themselves? I closed on June 1st, and the tenant is moving in July 1st. I guess I'm responsible for the utility for the month of June, but how do I get this? I didn't open an account myself, but the unit has electricity and gas - who is paying this bill? the seller? And when the tenant decides to open an account, will the entire month of bill go to them?