FreeNAS is a NAS server built on a minimal FreeBSD distro. Industry standard protocols such as CIFS, NFS, iSCSI, FTP are supported. All configuration can be completed through a web interface. Due to the small size FreeNAS can be run from Compact Flash, USB key or a standard hard drive installation. Version 0.69 was released January 17, 2009 adding TFTP, WOL and fixing some minor bugs. Check it out!
http://www.freenas.org
http://apps.sourceforge.net/phpbb/freenas/index.php