Hello,
I just want to tell you how i upgrade from PHP 4 to PHP 5:
I have got PHP 5.0.3 running with MySQL 4.x, at my Windows OS workstation just enabling the "extension=php_mysql.dll" (php.ini conf. file), and copying the "libmysql.dll" (comes with the zipped package) to "C:\Winnt\system32" path.