Thanks for the answer. I just got this working on Windows XP, with a few modifications. Here are my steps.
(snip)
<IfModule mime_module>
LoadModule php5_module "/xampp/apache/bin/php5apache2_2.dll"
AddType application/x-httpd-php-source .phps
AddType application/x-httpd-php .php .php5 .php4 .php3 .phtml .phpt
<Directory "/xampp/htdocs/xampp">
<IfModule php5_module>
<Files "status.php">
php_admin_flag safe_mode off
</Files>
</IfModule>
</Directory>
</IfModule>
(Note that this is taken from the same file in the 1.7.0 xampp distribution. If you run into trouble, check that conf file and make the new one match it.)
You should then be able to start the apache server with PHP 5.2.8. You can tail the G:\xampp\apache\logs\error.log file to see whether there are any errors on startup. If not, you should be able to see the XAMPP splash screen when you navigate to localhost.
Hope this helps the next guy.
cheers,
Jake