This is the reference guide for wxXml2 component. wxXml2 are C++ wrappers of libxml2 for the wxWidgets cross-platform GUI toolkit. wxXml2 is wxWidgets-licensed; libxml2 is MIT-licensed and libiconv (the dependency of libxml2) is LGPL-licensend.
Currently there is not a full tutorial but the usage of wxXml2 classes is pretty easy; just take a look at the The minimal sample of wxXml2 page to get an idea.
To build wxXml2 and integrate it in your program, look at the wxXml2 installation page.
Last, also look at wxXml2Wrappers and reference counting page for some important notes about wxXml2 classes usage.