raid & lvm

[SAM GIRAFFE]

hello,

i installed ubuntu server, and during the installation i selected to  
use lvm
ubuntu created one volume group called Ubuntu and a logical volume  
called root to mount the root partition

i have two hard drives, and would like to software mirror them

can i use dmraid package to mirror them now?
or will i have to reinstall ubuntu, make sure lvm is not selected  
during installation, then use dmraid to mirror the drives, and then  
use lvm to create volume groups?

is there any way to mirror the drives after lvm has already created a  
vg on one of the drives?

thanks...