At present the 64-bit OS is only available for OEM, that's because it
is for the Itanium High-End market only, but
The new AMD 32/64-bit and Intel Xeon 32/64-bit both should be
available in OEM and Retail (no supporting documents), but reasoning
is many users already have the AMD 32/64-bit capable
processors/chipsets and the new Intel Xeon 32/64-bit capable
processors/chipsets are already shipping from Dell and others - so
somewhere along the way these people are going to want the 64-bit OS,
as now they are stuck with the 32-bit OS installed when they bought
it - I being one have a new Dell 3.6Ghz Dual Xeon 32/64-bit
Processors, with only a 32-bit, standard WinXP OS - no coupons, no
upgrades to 64-bit when it becomes available (when ever MS releases
it - rumor has it latter part of this year or early 2005). So I'm
left to my own avail, although somewhere along the line, I'm sure Dell
will sendout correspondence to solicit additional sales for the new OS
when its available