Also, if you've reached the point where PDO is too restrictive for what you want to do, you should be knowledgeable enough to write your own db class that incorporates sql injection protection (since all that largely consists of is escaping strings).
http://www.google.com/search?q=php+mysql
Searching for PHP and MySQL yields tons of tutorials, code examples, and documentation related to the now-deprecated mysql interface. When I wrote my first comprehensive PHP application last year I spent half a day trying to determine best practices before finally settling on PDO. Newbies won't go through that effort, and will naively land on mysql rather than PDO or mysqli as likely as not.
PHP has been around forever and Google has a long memory. Unfortunately, for every good blog post/tutorial on PHP development there are 100 or more bad or out of date ones.