first setup your new partition and mount it under something like /mnt/home
Then make sure your logged in as root, and do cp -a /home/ /mnt/home/
Then delete all the files from /home the add
/dev/hdXX /home XXX defaults 0 2
to fstab, replacing the X's wit the approriate settings, then
And your done.
Thats the basics anyway, I would do a full backup of /home before proceeding.