IPTV is not as simple as "TV channels over the internet".
IPTV is a closed system, like the current cable network, but where the traffic is encapsulated into IP streams and routed over IP based devices. This makes it easy to take advantage of multicast rather than broadcast traffic to implement SDV, but it's still running over a closed private network. You can't plug an IPTV STB into any internet connection and have it work, nor can you receive the services on other IP based devices like a PC, you still need to be connected to the providers network.
AT&T's U-Verse service is probably the best example of IPTV around as it offers nearly 400 SD, and over 100 HD channels, all over VDSL.
"TV over the internet" such as Sky player, is Internet TV, an entirely different thing.