Wow!! We hacked up something similar few months back as a side project. Nice validation :). You have some real nice UX and figured out the pricing as well. Best wishes.
We have been getting some consistent traffic, but need more push to market ourselves. Got real good feedback from both users, friends and HN, but getting the real consumer to use it is the key I guess. You guys figured out the pricing, which is great and being an iphone app you can use the in-app purchasing. We were more web focussed. Also, not generating real phone numbers as you did.
I might still add some more features to it, but thinking about the direction right now :)
We didn't market enough and had some more features in mind to build. But this is a tough market given the fact that people have to remember your app when they actually need it.