I've been using a program called "DiskFactory" for about 4 years to make backup copies of my Master Disks. Works great. You can buy that at DiskFactory.com.
I recently switched over to RsMaster though, since it allows me to install activation on 'puters without a floppy. Awesome investment. You can find that at lrwsystems.com.
Generally, I'll make a backup of my live keys, and then lock them away and use the backups for Activation. That way when my PC dies, I've still got my keys.
Hope that helps...