Sharing folders on NTFS filesystems has always been a bit of a struggle in Ubuntu.
It seems that as of Ubuntu 9.10 if you take the 'Sharing Options' route, you are now informed to add usershare owner only = false to the [global] section of /etc/samba/smb.conf.
Sounds easy... ^^
Believe it or not this is an improvement on past Gnome/Ubuntu releases. Nevertheless, a block of jargon filled text asking a user to edit their smb.conf is a cumbersome, error prone and off-putting approach to take for a modern desktop environment.
In such a situation, surely there could be a simpler approach? When sharing a folder on an NTFS filesystem, a simple GUI could warn of any security risks, ask for an administrator password and then make the necessary changes.