VNC vs. X export

[ir0nkid at linuxjunkies.com]

>
> X can display remotely on a program-by-program basis.  VNC requires that
> you export the entire display, desktop and all.  Both can be tunnelled
> via SSH.
>

I have a similar question regarding the original post.  I also would like
to be able to remotely control my X.  I know how to use X applications
remotely by exporting the DISPLAY, or with ssh:

# ssh -X user at xapps

But that will only allow you to start a new app (say x-chat), and not the
one that is sitting on my machine at home (unless i am missing something)

a friend of mine was trying to tell me to run >gdm &   or >xdm  and this
should give me the destop manager login.  But what i would like to know is
if i can somehow use my desktop that is currently logged in.  I played
around for a bit trying to export the DISPLAY different ways (but i'm
still kinda new to it).

I also tried out the vnc server that comes with tightvnc, and have gotten
it to *kinda* give me a gnome destop (fonts are there) by modifying

~/.vnc/xstartup

by making the last line

gnome-wm &

But all this appears to do is just start it's own X server (apposed to
allowing me to use my account locally logged in.  Is there a way to do
this, and i have goofed somewhere?  Any input is appreciated.

thnx,

jacob