Added hard drives; how to configure raid?

[Reid Rivenburgh]

Hi.  I'm currently running Fedora 11 on an x86_64 system with an
nForce 680i motherboard.  I had a single drive in an LVM
configuration.  I just added a couple of 1.5 Tb hard drives to it, and
I think what I want to do is set them up in a RAID 1 configuration.
Is there an easy way to do that on an already-installed system?  The
guides I've found (including the official installation guide) describe
how it's done when installing Fedora, but I don't really want to
reinstall.  I've obviously never done this....  Thanks in advance for
any pointers!

-- 
Reid