1. Enabling Remote Desktop in Windows XP
Start > Settings > Control Panel > System > Remote (tab) > select “Allow users to connect remotely to this computer”
http://www.microsoft.com/windowsxp/using/mobility/getstarted/enableremote.mspx
2. Connect to another Windows XP computer using remote desktop
http://www.microsoft.com/windowsxp/using/mobility/getstarted/remoteintro.mspx