The XML Schema Working Group, part of the XML Activity, is responsible for the W3C's work on this topic -- for details see the Working Group's charter.
Of course, you can also parse XML data that you have already stored yourself into a memory buffer.
Thereafter, you can easily "explore" the tree to get your data.
To the best of my knowledge, the Incredible XML Parser is the best "non-validating C XML parser" currently available 😄 (and by a large margin! If you are still experiencing character encoding problems, I suggest you to convert your XML files to UTF-8 using a tool like iconv (precompiled win32 binary).
If you like this library, you can create a URL-Link towards this page from your website (use this URL: Parser.html).
For example, you start off referring to the model as "Product" but then you have this:class Contact : IData Error Info And later you say "That completes our Contact model".