I recently installed phing on Windows XP via PEAR. It works nicely out of the box on windows console (cmd), but would rather use Git bash and don’t want to switch to cmd just to run phing build. And it didn’t work, but fix is rather simple.
Phing creates file phing.bat in the PHP directory, so it makes only to put another file, named phing (executable) with content:
php -d html_errors=off -qC "C:\path_to_your\PHP\PEAR\phing.php" $@
And that’s it. Hope it was helpful :)