How do I switch LVM disks?

[Neal Becker]

I got a new disk, and created LVMs on it.  I copied the filesystems OK. 
But, how do I get the new disk mounted as /?  For that matter, what
determines what LVM gets mounted where?  I'm guessing it's part of the LVM
information.  I noticed that system-config-lvm has options to select where
logical partitions get mounted.

I hope I don't need to switch it by editing with system-config-lvm - because
if I mess that up, I'm basically screwed.

I tried editing grub.conf:

title Fedora Core (2.6.15-1.1948_FC5)
        root (hd0,2)
        kernel /vmlinuz-2.6.15-1.1948_FC5 ro root=/dev/VolGroup00/LogVol00
rhgb quiet
        initrd /initrd-2.6.15-1.1948_FC5.img
title Fedora Core (2.6.15-1.1948_FC5)#2
        root (hd0,2)
        kernel /vmlinuz-2.6.15-1.1948_FC5 ro root=/dev/7200rpm/LogVol02 rhgb
quiet
        initrd /initrd-2.6.15-1.1948_FC5.img

But if I select #2 it panics saying it can't find /dev/root, (or something
like that).
Here's some info:
lvm> lvscan
  ACTIVE            '/dev/7200rpm/LogVol03' [2.00 GB] inherit
  ACTIVE            '/dev/7200rpm/LogVol02' [53.50 GB] inherit
  ACTIVE            '/dev/VolGroup00/LogVol00' [53.59 GB] inherit
  ACTIVE            '/dev/VolGroup00/LogVol01' [1.94 GB] inherit
lvm> pvscan
  PV /dev/hdb4   VG 7200rpm      lvm2 [55.50 GB / 0    free]
  PV /dev/hda5   VG VolGroup00   lvm2 [55.56 GB / 32.00 MB free]
  PV /dev/hdb3                   lvm2 [196.11 MB]
  Total: 3 [111.26 GB] / in use: 2 [111.07 GB] / in no VG: 1 [196.11 MB]
lvm> vgscan
  Reading all physical volumes.  This may take a while...
  Found volume group "7200rpm" using metadata type lvm2
  Found volume group "VolGroup00" using metadata type lvm2