NASes

Here are a few open source NAS (Network Attached Storage)options.

Openfiler - http://www.openfiler.com

FreeNAS - http://www.freenas.org

OpenNAS - http://opennas.codigolivre.org.br/

As of 2009 the most complete is the Openfiler.  FreeNAS has more features, but it lacks the ability to partion the drive(s) from the GUI.  or as far as I know it does.  I don't think OpenNAS has a image to download yet ?

I have been using Openfiler for over a year and been pretty happy with how it performs.