HotScripts.com - A very large script archive, not everything is PHP.
MySQLdiff @ Freshmeat.net - There certainly is a MySQLdiff Project at Freshmeat.net.
PHP Archiv
The PHP-Resource - A nice little community where lots of topics (MySQL, PHP, ...) are discussed.
WebMasterEngine.Com - WebmasterEngine.Com is to be a complete webmaster resource. It consists of thousands of links to articles, web site & design tools, services, scripts, extras and other webmaster resources.
Links