You need to add an entry in the /etc/fstab file to allow any user to mount the drive. Here is the line you will need to add(I'm assuming your dvd drive is hdd):
Code:
/dev/hdd /mnt/dvd iso9660 noauto,user,ro 0 0
You will also need to create the /mnt/dvd directory.
Now any user should be able to mount the dvd drive.