Infoworld covered that the first HP hardware boxes with Windows Home Server are to go on sale worldwide very shortly.
Latest info from HP here: http://h71036.www7.hp.com/hho/cache/447351-0-0-225-121.html
According to Inforworld:
Other companies that plan to have Windows Home Server hardware available in the next six months include Iomega, Tranquil, Medion, and Fujitsu Siemens. Gateway and LaCie, in France, also have signed on to offer Windows Home Server products. System builders Ace Computers, Avantec, PC Club, and Universal Systems now offer Windows Home Server on custom boxes.