According to various sources, next week at CES Microsoft will be announcing the availability of iPTV via the Xbox. This will provide you with on-demand access to various programs. In addition, the next version of the Xbox is reported to have an HDMI port providing that iPTV with full 1080p goodness.
UPDATE: As expected Microsoft confirmed these reports about the Xbox 360 v2.
UPDATE: As we learned from the CES, the iPTV availability is true, but the HDMI rumor was not confirmed, and in fact Chris Satchell, Microsoft's General Manager of their game development group said:
"At the moment, everything you might have seen is just looking at our experimentation back in Redmond"
So basically, it could happen or it could not.