It's a bit of a job-
first you need to remove all the cluster setup ...
http://forum.r31skylineclub.com/index.php?topic=3732.0there is a heap of bolts, screws, wires and things to remove and loosen behind the cluster, down the sides of the dash as well...
the hard part is removing the metal *YES METAL* panel that runs along the very front of the dash, I think there a two bolts under plastic caps that hold it down... they are fun to remove you'll need a quality socket set. once you have them undone, it's a bit of a force but you can pop it off trying not to do too much damage to the windcreen or dashtop.
there are a few bolts underneath that- whisk them out again with the right tools.
with some force and maybe a mate, you can wriggle off the Dash with some force... be careful... and look out for any screws that you might have missed and be sure not to rip the loom apart in the process...
once you've done it and put it back in, it's a 20 min job.
goodluck.