From:

http://www.microsoft-watch.com/article2/0,1995,1581874,00.asp

The intersection of telephony and PCs. At last year's WinHEC, the "Athens" communications PC prototype, co-developed by Microsoft and Hewlett-Packard, stole the show. This year, Microsoft is promising to talk more about built-in Longhorn capabilities, such as voice over IP (VOIP) and call control for Bluetooth-enabled devices.