From the 360 blogs:
Sweet.A couple of days ago, a handful of screenshots arrived at our doorsteps hinting that the IPTV option for the Xbox 360 may be activated soon. The screenshots belong to a gamer who sent in his console for repair.
When he got his console back, an option for said feature has been added in the Dashboard. Microsoft just issued an statement about the matter stating that the leak is legit but that it doesn't intend to activate the service with the annual Fall update.
Here is the company's complete official statement:
Internet Protocol Television (IPTV) features will only be available from the Xbox 360 through a service provider who has deployed Xbox 360 with Microsoft Mediaroom (IPTV) services.
This was an isolated incident where these features were inadvertently exposed while the customer's console was being serviced and is unrelated to the Fall Update.
Xbox 360 with Microsoft Mediaroom (IPTV), will be available to service providers by the end of the year. Microsoft's IPTV service providers will ultimately determine the timing of Xbox 360 with Microsoft Mediaroom deployments.
As much as we want to try this feature as soon as possible, an end of the year launch date is not that bad. We wonder if Microsoft will be revealing this much at this point if the leak hasn't occurred.