Microsoft has squashed the rumor that IPTV could be a part of the Fall Dash update with this short note to Joystiq:

"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."

So it's up to the cable companies when you'll be able to get a 360 with DVR functionality? Great. I look forward to not getting one of these when they're released...in 2025.