You need to change your fstab to include the 'user' option. For example assuming your CD-ROM is /dev/cdrom, your Floppy drive is /dev/fd0 and your Zip drive is /dev/hdc then you would want something like the following in fstab
/dev/cdrom /mnt/cdrom iso9660 noauto,user,ro 0 0
/dev/fd0 /mnt/floppy auto noauto,user 0 0
/dev/hdc /mnt/zip auto noauto,user 0 0
Check out the manpage for mount for more options. Your normal user could then issue
to mount the Zip drive (for example).