Regarding the Nunez letter:

Text at:  http://www.sahuaro.f2s.com/peru.txt

or HTML at:  http://members.cox.net/vodhner/peru2.html

The first Microsoft argument (as quoted by Dr. Nunez per
the cited translation) very interesting.

1. The bill makes it compulsory for all public bodies to use
  only free software, that is to say open source software,
  which breaches the principles of equality before the law,
  that of non-discrimination and the right of free private
  enterprise, freedom of industry and of contract, protected
  by the constitution.

Microsoft argues that the state should not dictate the
standards for software that it would acquire.

Would Microsoft argue against a private corporation
decreeing an all-Microsoft shop?  Or wouldn't that be fair?