My old company offers "cloud" based private PBXes and there are a number of customers with users throughout the country (and offshore). This is using proper local phone numbers that both can be dialed out from and dialed in to but Skype can also be used alongside these lines in the system if you want cheaper calling rates. The systems are based off "PBX in a flash"
Skype Connect is Ok for international not a bit of an over kill for local NZ calling with packet delay etc.. I've tested it on our systems at work but to-date I don't know of anyone who has taken it up. As Skype is not a normal ISP your on your own if you have problems with setup..