Kerberizer adds GSSAPI Kerberos security to insecure Windows email and ftp clients (ones that normally send account names and passwords across the net in plain text). Where the server supports it, Kerberizer can also encrypt the traffic between the client and the server.
Kerberizer does this by adding itself to the Windows TCP/IP stack as an extension (it is a "Windows Sockets service provider"). It will work on any version of 32-bit Windows. But to preserve its security it should only be installed on an NTFS partition on Windows NT, 2000 or XP.
For more information see the Kerberizer Readme or go to the SourceForge project site.