I wanted to put /usr/local on its own partition, so I can preserve it during re-installs.

I tried to do this the last time I installed RH9, but for some reason, it didn't work. I generally pre-partition the drives using PartitionMagic, allocate them during setup, but allow Disk Druid to then reformat the partitions.

I'd like to move /usr/local onto a new partition, but am not sure exactly how to go about this. I think I could mount the new partiton manually, move everything under /usr/local onto it, and then set a mount point in fstab, leaving the /usr/local folder itself on /usr as the mount point.

I'd appreciate any advice.

First find which partition it is
This can be done by
cat /proc/partitions
or
fdisk -l /dev/hda
I think you can find which partition it is and mount it.
Now for your query about /usr/local create a new partition through partition magic or fdisk whichever you prefer
Find the partition number of the partition through
fdisk -l /dev/hda
mount the partition and copy the content of /usr/local
now do
rm -rf /usr/local/*
now modify your fstab and mount the created partition on /usr/local

My suggestion would be to do this a little more safely than rm -rf /usr/local/*. . .

If you are moving /usr/local to a new partition, mount that partition on /mnt (or wherever you want to, but it should not be /usr/local). do a:
This copies all of your data under /usr/local to /mnt, preserving symlinks, etc.
Edit your fstab and change the /usr/local mount line so that the partition you have mounted under /mnt will mount under /usr/local.
reboot.
If this doesn't work, you have not lost any of your data. The rm command will cause a loss of data. If it does work, you can then remove that data from the old partition and go on. . .
It should work just fine, I do it all the time. =-}

Thanks to both of you. I followed the first answer (which was basically what I had in mind), because I didn't see the second one in time. Anyway, it all worked.