SSH Tunnel SMB for Mac OS X
The harddisk on my Powerbook got full and I had to move my iTunes music collection to a Linux server. iTunes is quite nice and works with links (or aliases as Apple calls them) -- it even let's you play your purchased music. We chose Samba because NFS's security scheme is quite sketchy... anyway to inititiate the SSH tunnel type on the Mac (in iTerm):
sudo ssh -L139:host-ip:139 -p8888 german@dfl.ucsd.edu
After entering your Mac password (sudo) you have to enter your Linux password (ssh). Then go to the finder, press Apple-k, and enter:
smb://localhost/name-of-your-share
I guess a downside of this method is that you might not be able to use smb shares on your Mac... but you can always try to get a full blown VPN with IPSec;-)