This was a very useful article for me. Several of my programs stopped being able to save changes to their configurations or didn't work correctly because I hit the 300 MB limit of the root partition since I have installed a lot of different apps.
The following is what I used when moving folders to the media partition (example replacing {OriginalPath} with /Applications and {NewPath} with /var/Applications):
cp -R -pv {OriginalPath} {NewPath}
rm -rf {OriginalPath} && ln -s {NewPath} {OriginalPath}
I was able to move the following folders without any problems as well: /Library/Ringtones, /Library/Wallpaper, /System/Library/Fonts, and /var/opt (where Perl is installed).
One warning: it can be dangerous to move certain folders such as /usr, and likely others. I got a little carried away and tried to move /usr which made my iPhone not be able to launch any applications at first and when I tried restarting it, my iPhone kept rebooting itself. I managed to restore the phone to the latest patch but I lost all my apps and settings
BTW, pzuffa if you haven't figured out your problem yet - the command is LN (ell-n) not 1n (one-n), which is an abbreviation of link.