If you go on ESB Networks website you can find a domestic application form for a connection. As far as I know, you complete this, submit it and then they will inform you. However, I understand that you probably want the answer asap so their contact details are:
New ESB Networks Connections
(8 a.m. to 8 p.m. Monday to Saturday)
Phone 18 50 37 27 57
I have heard, not sure if its true, but you pay the cost of the digging of the trench and the pipes?? and they put in the rest. I'm not sure about this one though. Sorry I cant be of much help.