Courtesy of NeoWin:
It appears a tiny registry change on a machine running Windows XP SP2 will enable SP2's Concurrent Sessions for Remote Desktop. This allows more than one user to use the machine at the same time.
HKEY_LOCAL_MACHINE/System/CurrentControlSet/Control/Terminal Server/Licensing Core
Create a new DWORD entry "EnableConcurrentSessions" and assign a value of 1 to it. Concurrent Sessions is now enabled.
Microsoft's response to this matter in the SP2 newsgroups was:
"I am curious about your report that the Registry Key you mentioned is allowing you to log on with multiple users concurrently. This registry key should do nothing. Could you please confirm that you are able to have two users logged on to your XP SP2 box at the same time? And further what changes you made to make this possible? "
We exclusively revealed that Windows XP SP2 would contain Concurrent Sessions back in April 2003, since then many sites have claimed SP2 wouldn't contain Concurrent Sessions but it shall.
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