Vonage, a pioneer in the fixed line VoIP market, recently announced it was developing a downloadable client for the iPhone. Reuters reports the stock is up 35%. (CORRECTION: On Aug 17th, Vonage closed at $0.38, on Aug 27th, it closed at $1.99, it's up more than 500%).
There is growing interest in downloadable VoIP clients for mobile phones. Skype, the undisputed VoIP leader, developed a client for the iPhone which has been downloaded more than 4 million times.
Unfortunately, mobile operators typically have not been able to respond in kind. Therefore, high-value customers are putting these mobile VoIP clients on Wi-Fi-enabled smartphones and bypassing high international calling rates, and/or using the clients to bypass roaming rates when traveling abroad.