If you're not comfortable downloading C source files and compiling them on your windows machine you'll find it much easier to take the following approach to setting up your system to use libxml. Even if you dont end up using XApp long term the following tools will be certainly be useful (essential even) to you over time if you're interested in developing XML/XSLT web apps
For many years now the standrard Perl distribution for win32 has been popularly supplied by Activestate. They provide an interactive .exe installer which will guide you through the process. See their website for details.
If compiling C sources doesn't sound too appealing you might instead opt for downloading Igor Zlatovic's handy pre-compiled Win32 binary for libxml and libxslt. You'll also need iconv and zlib which are available from the same place.
Unless you're looking to use and extend the libraries in a project of your own the only files you'll really need out of the ZIP files you download will be the DLLs (libxml.dll, libxslt.dll, libexslt.dll, iconv.dll and zlib1.dll) which you should place somewhere that is reachable by your system PATH variable, c:/windows/system32 is probably a sensible place
While you're at it you should extract the command line executables (all the .exe's from the ZIPs you download) into a folder somewhere, say c:/tools/libxml/
You could download the cpan distributions of both XML::LibXML and XML::LibXSLT directly and use a make clone to install them, but if you're on a Win32 box I'd reccomend using the PPM (perl package manager) install provided by Randy Kobes.
Here's how (I'm assuming you actually have perl installed on your machine)...
ppmin a DOS window to start the PPM shell
set repository theoryx5 http://theoryx5.uwinnipeg.ca/ppmpackages/
If you're getting errors like Could not locate a PPD file for package it could be that you're firewall is not allowing you to connect to the PPM repository. Good luck sorting that out
If alls gone well you should now be able to load the LibXML module with a simple test like this from the command line...
C:\perl> perl -MXML::LibXML
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