The Gnome Project has posted version 2.6.8 of libxml2, the open source XML C library for Gnome. This release improves support for the W3C XML schema language, fixes a few bugs, and attempts a couple of optimizations. They've also released version 1.1.5 of libxslt, the GNOME XSLT library for C and C++. This is also a bug fix release. Both versions are only available in CVS for the time being. Sources and binaries have not yet been posted.
Toni Uusitalo has posted Parsifal 0.7.5, a minimal, non-validating XML parser written in ANSI C. The API is based on SAX2. Parsifal doesn't yet catch all the well-formedness errors it should, but unlike a lot of so-called fast parsers the author does seem to realize this is important, and is working on fixing the problems. I can't recommend this parser just yet, but by the time it hits 1.0, it may be worthy addition to the C programmer's toolbox. Version 0.75 fixes one nasty bug. Parsifal is in the public domain.