Originally Posted by
nmenaker
I think you'll find that the vonage app allows calling over 3G, but it will use minutes from your providor, so it isn't free. But, it would be a good use to call LD to abroad at cheaper rates than AT&T for example. I just use onesuite for that.
Looks like when you attempt to make a call when you're not connected to wifi, the Vonage app just causes your phone to make a standard voice call (not over the data network). That's why it uses up your minutes. It may do some magic like Truphone Anywhere and dial a domestic gateway number which puts the international leg over Vonage's IP network, but it doesn't actually use the 3G data connection.
Hopefully this will change soon. Truphone actually addresses calls over 3G networks on
this page:
Truphone over 3G
Truphone works over 3G - this is great if you've got a generous (or 'all-you-can-eat') data tariff, but do note that cost, quality and availability of 3G services vary enormously.
While it is possible to talk for free walking down the street, it is also possible to run up a huge bill this way. Be sure to check both that your operator allows this and what your tariff is - especially when you're roaming overseas. It is great though.
Please note that this is in beta. Not all 3G networks were created equal or are quite ready for VoIP. Not currently available for iPhone application.
(Emphasis mine.)