You can't just change the permissions on the mount point or partition. You need to pass some options to the mount command, either on the command line or in /etc/fstab to make it readable by those who should have access. Or, for a quick and dirty fix: Specify umask=000 on the "option" part of the line in /etc/fstab. That will make all files on the partition readable/deletable and executable by
everyone. This is of course a security hazard but I have outlined another neater way
here.
Håkan