PHP. No doubt about it. Once you get the hang of it, almost nothing is impossible to do anymore. You must have a server that runs PHP though (almost all webhosts nowadays as it's almost as big as microsofts ASP).
http://php.net - The official php-site with the manual and function references
http://phpfreaks.com - A good forum and some good tutorials/examples
http://hotscripts.com/PHP - Thousands of free scripts, and also tutorials and links to other PHP-sites
mangemuck at gmail dot com - The email to me who can help you
