XIST (simple, free license) is a very capable package for XML and HTML processing and generation. In the maintainers' words:
XIST is an extensible HTML/XML generator written in Python. XIST is also a DOM parser (built on top of SAX2) with a very simple and Pythonesque tree API. Every XML element type corresponds to a Python class, and these Python classes provide a conversion method to transform the XML tree (e.g. into HTML). XIST can be considered "object oriented XSL".
I covered it recently in "Writing and Reading XML with XIST". There are some API tweaks and bug fixes as well as some test suite infrastructure changes. The full, long list of changes is given in Walter Dörwald's announcement.