This issue is becoming more and more prevalent with OS X users. Apparently, there is no easy way to set up permissions and file-sharring in OS X to share an extermal hard drive over a network. (You can do it yourself if you’re good at UNIX and are very comfortable with mucking around in NetInfo database.)
Enter Sharepoints (v3.5.4). It sports a clean graphical interface which runs as either a standalone app, or Preference pane.
Speculation about Apple’s purchase and integration of this great interface tool abounds.
Check it out: Sharepoints