Ugh.  I hate paperwork. :)

Most of ZSI is covered by an MIT/X Consortium copyright, as found
in doc/zsi.tex.

The wsdl2python tools are covered by an LBNL BSD-style license, as found
in ZSI/LBNLCopyright.

Most of the code in wstools is covered by the Zope Public License,
which is a certified open source license that is GPL compatible.
See ZSI/wstools/ZPL for details.
