Microsoft Knowledge Base Article 316353 contains the following summary:

This step-by-step article describes how to configure a user account to use a roaming user profile. To do so, you must create a shared folder to store roaming user profiles, and then configure the user account to use a roaming user profile. After you complete this procedure, the user's profile, including the user's unique desktop settings, is stored on a server, and the profile is available to the user when the user logs on to any Windows NT 4.0-based computer in the domain.