The solution to install apache 2.0.4x and PHP 4.2.X I have found is that you cannot load as modules the php dlls unless you download the apache source and proceed to compile it yourself, for your own specifications.
To say that Im utterly disapointed with apache, is to put it mildly. I have stopped recomending my customers to use apache, as of late there seems to exist a trend from apache foundation to behave like complete jerks, and ignore the coments and ideas people bring in.
Having said this, if you still wish to install the crumy 2.0.4x versions ( I've gone back to 1.3.27 ) in order tonm install php what yu must do, is unless you how to compile it yourself, install php as a CGI type of appplication.
How we do this? simple, unzip the php version you have, into a folder named PHP on your apache root folder ( C:\Apache\php ).
Next create your php.ini as the tutorial explained, and then edit your apache httpd.conf file. In this file go to the end of it, to the very last line, and hit enter once to leave a blank line, then proceed to write there the lines I put here:
ScriptAlias /php "C:/Apache/php/"
Action application/x-httpd-php "/php/php.exe"
AddType application/x-httpd-php .php4 .php .phtml .php3
AddType application/x-httpd-php-source .phps
Allow from all
Reboot your machine, and test php as explained in the tutorial. On word of advice I'd give is to create your web folder outside apache's root folder, since its easier not mess up the whole thing this way.
Anyway, this is the solution for installing apache and php on Windows XP Professional ( it works even if you have installed SP1 ).
Hope this helps you all, and btw Im running PHP 4.2.4 dev and works like a charm, not a single glitch on any servers Ive tried it on.