StarWind Free version is a free iSCSI Target that converts any Windows server into a block-level storage server or a SAN in less than 10 minutes.  This is a fully functional product at no cost. 

  •  Large 2 TB storage capacity
  •  Virtualization environment support for VMware, Microsoft Hyper-V and XenServer
  •  Enhances VMware environments by enabling VMotion, VMware HA, DRS and VCB
  •  Supports Windows server clustering for any application including SQL Server, Exchange, SharePoint

http://www.starwindsoftware.com/free