I originally signed up with Vonage because it was inexpensive and it gave me unlimited calls to France (and other countries) where all my friends and family still are. As my fiance and I are planning our one-year trip around the globe, I started looking into getting Vonage on my iPhone so I can make calls from my iPhone, either over 3G or wifi, using my Vonage plan.
There are many reports showing that Vonage is currently working on an iPhone app but it's probably not going to happen anytime soon. By digging a little more, I found an article that shows you how to set up Vonage on your iphone by using your Vonage line as a SIP line.
First, you have to find out your Vonage SIP credentials. To do so, open your internet browser from your house and point it to:
Replace USERNAME and PASSWORD by your Vonage account username and password.
This is going to open a page with a bunch of information. The information we need is at the top of the page. You are looking for something like that:
Next step is downloading an SIP client for your iPhone. I recommend using Fring as it can be downloaded for free from the App Store. If your iPhone is jailbroken, you can also download SIPhone from Cydia.
Launch Fring then sign up or login with your existing account. Go to More > Add-ons > SIP > Other.
Fill out the required fields as follow:
User ID = ProxyUserName
Password = ProxyUserPassword
Proxy = a.vonim.com:10000
Save these settings. You can now place a call from your iPhone using your Vonage account, assuming you have wifi connectivity. If your iPhone is jailbroken, download VoIPover3G from Cydia and you will also be able to use Vonage from your iPhone over 3G.
It works great but for some reason, I can't have it place international calls. Every time I try to call France, it gives me an error message. It's still pretty awesome that you can use your Vonage account to place calls for free over wifi and 3G.
That's a pretty sweet hack, eh! What do you think?