In tips 4135 and 4136, I described configuring Remote Assistance in Windows XP.

Microsoft Knowledge Base Article 306800 contains the following summary:

This step-by step article describes how to provide help by using the Remote Assistance feature in Windows XP in response to a Windows Messenger invitation. Remote Assistance enables you to establish a connection to a remote computer through the Internet. This connection can be used to view the computer screen, participate in real-time chat, and remotely control that computer (when you have permission to do so).