Paul DuBois has released xmlformat 1.02 an open source pretty-printer for XML documents written in Perl (or Ruby) that can adjust indentation, line-breaking, and text wrapping on a per-element basis. Version 1.0.2 adds options for in-place formatting and backup creation. xmlformat is published under a BSD license.
Engage Interactive has updated two open source XML parsers written in PHP. SAXY 0.5 exposes a SAX like interface. DOMIT! 0.6 exposes an API based on the Document Object Model (DOM) Level 1. These releases improve performance. Both are published under the GPL.