Aswath,

Certainly VXML could be used, as could any number of voice response or prompt/reply technologies. I question, though, whether it would be cost-effective for a VoIP service provider to invest in building an automated system to do location updates when they're providing the capability solely to meet a regulatory requirement, and expect that very few users will actually make use of it.

I thought that because they will have web based update mechanism in place, adding VXML server is only an incremental cost. In any event it is certainly a better alternative than setting up customer service representatives or reject it saying that timely updates may not happen.

Exactly the idea I had to propose to Vonage..Pass on location info mandate to end user-let them register themselves on their website in similar way :

I would add 2 more steps to your list-

Enter NPA-XXX or your PSTN Phone number you have/had prior to VoIP service

Enter Broadband service provider name:

Anish