I was really excited at the earlier news about the availability of the Vonage iPhone VOIP App. I have been a Vonage customer for a long time and therefore was excited to try out Vonage on my iPhone.

I actually would have liked after the free download of the Vonage App to log in with my existing Vonage account, but this is not supported.
This means you need to register new even if you are already a Vonage customer. What is up with that?
Then I got completely stuck because the Vonage iPhone App requires a U.S. based iPhone phone number to register for an account.
I am located in Germany these days and I have a German iPhone number.
So even if you get the Vonage iPhone app to work it does not support inbound calls. You only can make international calls at a discount. You can call Afghanistan for $0.70-$1.25 or Germany for $0.02-$0.27. This is in itself a very nice offer, but it is the only one.
What I expect from the Vonage iPhone App is an extension of my existing Vonage account to become mobile. I want to be able to be called on my U.S. Vonage phone number and pick it up on my iPhone while travelling. I want to make international calls on my iPhone via the Vonage app under my current U.S. Vonage number.

Until this is supported the Vonage App is only a first step to getting VOIP onto the iPhone, but it is not enough, at least for me.