no dont remove lvm1. keep both lvm1 and lvm2.
if you have an older version of lvm1 installed, you'll probably get an error complaing about conflicts if you try to install lvm2. so first upgrade your lvm1 to lvm-1.0.3-17. it along with almost all required upgrades can be found at
here r wut u need to install or upgrade before upgrading to kernel 2.6:
almost all of them can be found at the URL above. if you are using rh9, some important notes can be found here