Problem:

How do I enable Remote Desktop in Windows XP?

Solution:

You'll need to right-click on 'My Computer'->Properties and make a note of your computer name (under 'Computer Name' tab).

Then go to the 'Remote' tab; tick 'Allow users to connect remotely'.
Click on 'Select Remote Users'.
Add your username (or who ever you want to have access) as a remote user.

Now the user can connect either locally or via the VPN
Then at they can use 'Start->All Programs->Accessories->Communications->Remote Desktop Connection' to connect to the computer name that you made a note of above....