Can't be done. Terminal Server is on Windows 2000 Server SKUs. XP allows for Remote Desktop Connections (RDP 5.1, vs 5.0 in W2K), W2K3 (RDP 5.2) also allows TS functionality. Vista will also allow remote connection as well.
But for 2000 Pro, nope. Though given that W2K Pro is already in extended support and only getting security updates, an upgrade plan to XP or Vista needs to be in the planning stages and approaching deployment.