CBT Tape
The cbt tape is a collection of freeware almost all open-source distribution
for the ibm mainframe mvs and os/390 operating system environment. the entire collection of free software can be downloaded.
http://www.cbttape.org/
Mark's MVS Utilities
Mark's mvs utilities - rexx & tso clists, ispf edit macros, sample jobs, documentation and more!
http://home.flash.net/~mzelden/mvsutil.html
Planet MVS
Planet mvs has mainframe freeware and
information
http://planetmvs.com/