FreeNAS is an embedded open source NAS (Network-Attached Storage) distribution based on FreeBSD, supporting the following protocols: CIFS (samba), FTP, NFS, TFTP, AFP, RSYNC, Unison, iSCSI (initiator and target) and UPnP.
It supports Software RAID (0,1,5), ZFS, disk encryption, S.M.A.R.T/email monitoring with a WEB configuration interface (from m0n0wall).
FreeNAS can be installed on Compact Flash/USB key, hard drive or booted from LiveCD.
FreeNAS image files suitable for most people are available on SourceForge: FreeNAS Stable Releases
This is where you can download the latest, stable versions to install on your hardware.