German Computer magazine C'T (Heise) is describing in its current print issue how to change Windows XP Home to a Windows XP Professional version before install.
Microsoft is not going to like this. The C'T magazine apparently found out that by changing 2 bytes in the installation file of Windows XP Home, it will install a Windows Professional. Some functions are missing, but Remote Desktop and User management and enhanced security features are present.
I could not find write-up of the instructions online yet. C'Ts online site is not reporting about it - guess they want to maximize print magazine sales. The article is in the c't 12/05 on page 148. The hack requires several steps. The major change is in a registry file setupreg.hiv in the i386 folder. The article is 8 pages long, so I guess you have to get the magazine to get it right.
Story via I4U (US) via silicon.de (German).