If it's empty it's just two commands (as root, of course)
vgreduce VolGroup00 /dev/sdb2
If it was in use, it's no big deal. You'd just have an extra step of pvmove'ing the data off of that PV before doing the above.
That would be
pvmove /dev/sdb2 /dev/<dest-volume>
There is a bug in LVM (per Red Hat) where it can hang using the above command IF there are multiple LV's on the PV.
It doesn't always hang, but to be on the safe side in that case you could move each LV individually.
List what is on the PV first.
pvdisplay --maps /dev/sdb2
pvmove -n <LV name> /dev/sdb2 /dev/<dest-volume>
for each Logical Volume.