We had a chance to check out Microsoft's IPTV offering for Xbox 360, announced earlier this week during Bill Gates' CES keynote, and get answers to some of the questions that have been nagging at us since first hearing about the service. Though Microsoft hasn't announced any providers for the service yet, both AT&T and Verizon -- as well as fourteen other telcos around the world -- use Microsoft's IPTV middleware platform to provide television over fiber, so they seem like likely candidates when the service debuts holiday season '07.Of course, if you're considering the DVR functionality, the Xbox 360's anemic 20GB hard drive won't get you very far. A Microsoft rep said the file sizes are dependent not only on the resolution of the feed, but the compression used by the provider; however, one could probably assume that the Xbox Live Video Marketplace's videos would be roughly analogous in size. Regardless, we'd expect an update to the drive before IPTV launches. Because IPTV uses software, not a hardware tuner, to decode the signal, the number of streams that can be simultaneously recorded is limited solely by internet and hard drive bandwidth. In addition, IPTV is capable of offering more HD channels than other platforms, like cable or satellite. Because the service shares the same connection as your phone and internet connection, it can provide telco caller-ID and features like teleconferencing have "been discussed." Perhaps the biggest question we have is whether or not any of this functionality would (or could) be made available to gamers who don't (or can't) get IPTV service in their area. Microsoft isn't saying anything but, considering the small amount of consumers with fiber service to the home, we certainly hope so.