http://kreaper.blogsome.com/quick-and-dirty-guide-to-iscsi-implementation/

Excerpt
iSCSI (Internet Small Computer System Interface), an IP-based storage networking standard for connecting data storage entities, developed by the Internet Engineering Task Force (IETF). Essentially a protocol carrying SCSI commands over IP networks, iSCSI can be a cheap and effective alternative for storage administrators who are otherwise struggling to strike a balance between the high-cost and complex implementations of FC-SAN (Fibre Channel Storage Area Networks) and the performance limitations and overhead of NAS (Network Attached Storage).

This article desribes the iSCSI protocol and provides a detailed step-by-step guide of implementing a iSCSI network.