http://www.familyhandyman.com/plumbi...leaks/view-all
I don't remember exactly, but I thought anything from the wall pipe to the appliance could be done by the home owner. I would just give 311 a quick call. It is easy to do, use gas fitting tape, it's yellow. I think you are also supposed to replace the flex line when you replace the appliance. They shouldn't be re-used.