Microsoft is notorious for changing the names of features in OS upgrades and giving new features less-than-intuitive names. For example, many people are confused about the difference between two similarly named Windows XP features: Remote Assistance and Remote Desktop. What's Remote Desktop all about?
Like Remote Assistance, Remote Desktop leverages Microsoft's RDP to provide a remote control environment in the vein of terminal services. Although you can certainly use Remote Desktop to support an XP user, Remote Desktop is intended primarily as a facility to let XP users access their own systems from remote locations—for example, a telecommuter accessing an office system from home or an office worker accessing a home system.
You can configure Remote Desktop through the GUI or through Group Policy. In fact, you enable Remote Desktop from the same place that you enable Remote Assistance—the Control Panel System applet's Remote tab. Like Remote Assistance, Remote Desktop is disabled by default. To enable Remote Desktop, select the Allow users to connect remotely to this desktop check box. Although the currently logged-on user will automatically gain access, you might also want to grant access to additional users or groups. To do so, click the Select Remote Users button and add the appropriate users or groups in the resulting field. (You can select these users or groups from the local computer's account database or from a Windows NT or Active Directory—AD—domain.) Remote Desktop's Group Policy settings let you enable or disable the tool and configure its behavior. Group Policy settings always override any configuration that the user specifies in the System applet.
If you're interested in advanced Remote Desktop tweaks and learning how to install the Remote Desktop Web Connection—the new name for the Terminal Services Advanced Client (TSAC)—which permits browser-based Remote Desktop access to an XP system, I recommend searching the XP section of the Microsoft Product Support Services (PSS) Web site. There, you'll find articles such as "HOW TO: Turn On Remote Desktop Automatic Logon in Windows XP" (http://support.microsoft.com/default.aspx?scid=kb;en-us;q281262), which describes how to configure Remote Desktop to automatically log on to a connecting system.