Vonage said that it will start offering VoIP phones that operate on Wi-Fi networks later this year: The phones will let subscribers make and receive phone calls when in range of a Wi-Fi network, either in their homes or public places. A Vonage exec said the move is in response to AT&T's announcement that it is offering VoIP in Texas and New Jersey.
The market for VoIP services is definitely getting crowded so anything that can differentiate a service will help. Vonage has a market leadership position as an early VoIP provider so it makes sense for it to be a leader in extending VoIP to Wi-Fi networks.
I suspect that VoIP Wi-Fi phones will be most useful in homes or businesses. Users will be disappointed if they hope to carry the phone around everywhere and expect it to work like a cell phone. The phones will only work in very limited areas outside of the home and office. Vonage and any other provider that offers such a service will have to be very careful how they market it.
Vonage doesn't seem to have issued an official announcement with any more information about the service.