You can download the latest version of iSCSI Initiator for Windows 2000, 2003 and XP. This will upgrade any previously installed version to the latest version:

https://www.microsoft.com/download/details.aspx?id=18986

You can download old releases of pfSense, all the way back to 1.0.1, from here:

https://atxfiles.pfsense.org/mirror/downloads/old/