"Yes, we are offering an HDMI port for Xbox 360 simply as another choice in Xbox 360 owners' games and entertainment experience. Retailers are gradually introducing HDMI-enabled Xbox 360s into the channel to meet demand."
How do you know if your new $350 Xbox 360 will have HDMI out? Simple enough: according to Microsoft PR, the applicable systems will now sport an HDMI logo, so keep an eye out for that and you'll be all set.
Update: We also asked if these new systems would ship with cooler 65nm chips and quieter DVD drives, but all we got back was the usual song and dance about "not commenting on details of specific components or manufacturing processes." In other words, if you want to see if Microsoft switched out their chips, you'll likely have to run to the store, buy another Xbox, and tear it down for yourself, because Xbox isn't engaging consumers otherwise.