i'm sorry for my prev quotes,
Windows XP 64Bit is still in Beta stages, but will release final version within 3-4 months.
from Micosoft, Windows Server 2003 for 64-Bit is available.
SQL Server 2000 is also available as a 64bit edition.
Microsoft is fully prepared for the coming 64bit era.
and all their future releases will feature 64bit editions (.NET 2.0 (VS2005), SQLserver2005, Windows code name "LongHorn" etc)
.Net rox !