The floppy disk drive connects via a USB interface. Red Hat 9.0 should already have created a directory to mount it in (/mnt/floppy); if not, create it manually as root:
$ mkdir /mnt/floppy
Then you can mount/unmount the floppy disk using:
$ mount /dev/sda /mnt/floppy $ umount /dev/sda
Altenatively, KDiskFree allows you to mount and unmount drives via a graphical interface. Simply type kdf in command mode, and right-click on the drive you want to mount/unmount. You do not have to be root in that case.