HD Install :: Own partitions for /home & /var

I did a debian install and everything is in hda1 except swap in hda5. I have 2 more partitions, hda3 & hda4. I would like to have /var on hda3 and /home on hda4. No problems changing /etc/fstab mount points, but how do I ensure everything is copied over properly, including symlinks etc.? Would it be safe to make the changes from a running system, or would I be better working from a live cd? Cheers.

original here.