Microsoft Knowledge Base Article 314537 contains the following summary:
Increasingly, users of wireless mobile devices require access to the functionality of their desktop computers.
Windows XP and Windows 2000 permit you to do this. By using the Handheld PC or the Pocket PC, you can connect
to an application server and run programs just as if you were sitting at the server computer itself. Connections
to application servers can be made across wireless local area networks (LANs), or across the Internet by using virtual
private networking (VPN).
To use the Handheld PC and the Pocket PC as remote terminals, you must first set up an application server. Generally, your application server will be your regular desktop computer in your office. If the Windows Terminal Services client software is not installed on your Handheld PC or the Pocket PC, you must install it. After it is installed, the Terminal Services client software permits you to connect to the application server and run programs.
This article explains how to use the Handheld PC and the Pocket PC as remote terminals to desktop computers that are running Windows XP Professional, Windows 2000 Server, and Windows 2000 Advanced Server.