I would check out this article by Renata Silva of Siemens:

Billing and Provisioning for Long-Term IPTV Success
Converge! Network Digest - January 11, 2006

"IPTV is the new battlefield for gaining the residential customer base of the future. More interactive entertainment and communication options – pay-per-view, high-definition programming, video conferencing and distance learning, for example – will surely capture consumer attention. However, the real winners of the new residential services dollar will not likely be the operators with the swankiest technology offerings, but those who can deliver and interact with customers without hitches. In other words, the smooth provisioning and billing of services."