[CentOS] Add more space to LVM

I have a database server that is running out of space. All my databases are being stored in a 80G /opt partition. Because I'm using LVM, wouldn't I be able to pop the HDDs (a h/w raid volume) in, add it to the LVM, and resize my ext3 /opt partition? Everything that I've been reading says this is possible, but I'm not sure. Has anyone done this and are there any pitfalls to watch out for? Is there a better way? I've thought about just rebuilding the server and restoring the databases from a backup on the new setup. Any suggestions on proper path would be appreciated. I'm running the current version of CentOS 5.

Regards,

Todd