Vonage started offering Unlimited Calls to India under its $24.99/m existing plan recently that include both landlines and cell phones. The 2 Months free offer is still available, if you haven’t signed up yet.
Today, Vonage released a Mobile application that can be installed on Blackberry, iPhone or iPod touch that will allow you to make international calls right from your Mobile at Vonage rates. It uses WiFi if available. Otherwise it uses your normal voice minutes on your Mobile like you are making a local call even when you are make an international calls.
Remember you will pay for Vonage International Calling Rates for each call you make, in addition to your cell phone minutes when you use cell phone network instead of WiFi.
It is bad you can not use your existing Vonage account to this mobile application. Hope Vonage will soon allow that too. You need to setup a credit or debit card and pay per use. I guess, Vonage will soon allow to connect your existing account and share that number, may be at a small fee.