external hard drive across network

It is possible to view and edit an external hard drive connected to the Apple TV 1 across a network from a mac/PC?  My brother is ‘acquiring’ a first gen model (I have ATV2 so can’t help him on this), and currently had all his movies/video on an external drive connected to his laptop running XBMC.  However, he also has software that downloads torrents directly to the external drive that can be controlled remotely.  So ideally he’d like to be able to still download files directly to the drive whilst connected to the ATV, rather than download to the laptop and manually move across.

I know you can ftp into the ATV, does the external drive show up there?

Yes, aTV Flash includes a ‘File Sharing’ option (accessible through the Maintenance --> Settings menu). This allows the AppleTV to share any connected drives using SMB (or FTP).