MathDOM is a set of Python  modules (using PyXML or
lxml, and pyparsing) that import mathematical terms
as a Content MathML DOM. It currently parses MathML
and literal infix terms into a DOM document and writes
out MathML and literal infix/prefix/postfix/Python
terms. The DOM elements are enhanced by domain specific
methods that make using the DOM a little easier.
Implementations based on PyXML and lxml/libxml2 are
available.

WWW:   http://pypi.python.org/pypi/mathdom/