HD Photo, this is th new name of the image format from Microsoft that they want to replace JPEG, PNG, Raw and GIF. It was previously known -at launch time- as Windows Media Photo and it is now fully integrated into Windows Vista.
Adobe Photoshop will support this format through a plugin to donwload from a Microsoft web site. For the time being, this is only a beta version for Windows, but a Mac version is under preparation.
The format should be natively supported soon (within 12 to 18 months!) by digital camera manufacturers. It works with both Photoshop CS2 and CS3.
PS: Really! everybody is trying to stick HD to anything that remotely looks like image-related, even when there is no objective reason for it (apart from the media attention magnet it becomes).