To get the PHP version as well as the Apache version of the current host build, you will need the PHP function apache_get_version():
$ver = apache_get_version();
Apache/2.2.6 (Win32) PHP/5.2.5
Which returns a string containing the Apache version number (2.2.6) as well as that of PHP (5.2.5).
You can also get the PHP version by: