VNC Session Manager adds the nessary glue code between VNC's two execution modes that enables xdm based login to disconnected sessions. i.e. it provides a 'Terminal Services' like login for *nix based vnc servers.
NetStation is a linux distribution for diskless thin clients terminals using standard x86 hardware. It can boot from network, floppy or flash-disk and connect to an application server using VNC, RDP, XDM, SSH, Telnet or Citrix ICA.