I’ve finally dug up what I consider to be difinitive enough information on the possible Windows XP - Windows XP 64 exchange. In a word, it’s true. BUT, there is one string. I’ll let the words of my contact, Josh, tell the tale -

I work on the Waggener Edstrom Windows Client team. My colleague Elizabeth Herrera Smith said you’d like a contact who can answer questions about Windows XP Professional x64 Edition. I understand you need to confirm if customers with 32-bit Windows XP can upgrade to x64 Edition at no extra cost. The answer is yes, they can upgrade at no extra cost through the technology exchange program. This is a program that allows customers to buy x64 hardware with 32-bit Windows today and move to 64-bit when it is available. This can be an OEM or System Builder machine, or even a PC that the customer builds on his/her own. Customers should visit their PC manufacturer’s website to see if they are offering this program. Please note: Windows XP Home Edition customers who have x64 hardware and wish to move to Windows XP Professional x64 Edition when it is available need to upgrade from Home Edition to Windows XP Professional Edition first.

So, this is a Christmas present for XP Pro users and a little lump of coal for XP Home users. At least those of us using 64-bit hardware aren’t faced with forking over another $200 (plus or mius) for a copy of a real 64-bit operatins system!