"The 64-bit edition of Windows XP designed for the Intel's Itanium 2 processor was released to manufacturing Friday, alongside Windows Server 2003. To emphasize the updated nature of the release, Microsoft has named the desktop operating system Windows XP 64-Bit Edition Version 2003. Windows Server 2003 Datacenter and Enterprise Editions will also feature 64-bit flavors of Redmond's new server platform."
Source: http://www.betanews.com/article.php3?sid=1048903653