The ElementTree library provides an Element type, which is a simple but flexible container object, designed to store hierarchical data structures such as simplified XML infosets. The library also provides support for reading and writing Element structures as XML.
The Element type is available as a pure-Python implementation for Python 1.5.2 and later. A high-performance C implementation is also available.
Both the original implementation and the C implementation are part of Python's standard library (package xml.etree) since Python 2.5.
For more information, downloads, and add-ons, see: http://effbot.org/zone/element-index.htm
There is also lxml.etree, an implementation of the ElementTree API in lxml, a library which is built on top of libxml2. lxml is really fast and has many extensions exposing advanced libxml2/libxslt features: