#problem Web callbacks suck in development. Your dev box must be accessible from the web for the idea to work.
Specifically, when I'm working with TelAPI, I want to be able to develop locally. I have to set up an account in TelAPI and tell it what url to post data to when it has an event.
http://mydevbox.myproject.com:8080
If you are in a position to make your dev box accesible from the web, you're lucky. But, I do not always have this ability.
#solution - proxy