As far as I know, there is no RDP server for the N8x0. Maybe XRDP was ported or something, but that works by looping a VNC connection and weird stuff like that (aka it would kill the processor on the already overtaxed n8x0). So, like fatalsaint said, use x11vnc for vnc.

X-forwarding via SSH (it seems you can already SSH from your debian box) does not seem to work with OS2008, but i have heard it works on debian running on the n8x0.