I had vonage for a year..personally i did not like them becasue of the hardware issues.. You need an external router...i now have
www.skype.com . I have there skype out service which includes a phone number and voice mail. You just buy skype minutes and when you get low buy more. Plus you do not need an external router. I have 2 of there phones and they just plug into your usb..
Mr. Romance