to be honest the sites are not exactly clear on what OEM's are, you just type in Windows XP Home and it gives you that option.
Therein lies the problem ....
As Saab quite rightly pointed out, you can buy it ....
Problem is your average Joe Bloggs is unlikely to be buying it for the correct reason as far as licensing goes.
That's the point I was trying to get accross, watch the licensing. Microsoft do view "mischanneling" as piracy.
Hope that helps clarify.