PHP Performance Tips from Stanislav Malyshev
php100.wordpress.com
php100.wordpress.com
Stas (who works for Zend) also did a quite nice post about those (in)famous PHP performance tips from Google: http://php100.wordpress.com/2009/06/26/php-performance-googl...
But this does make a great place to start if your little php site is starting to get more traffic then you dared hope and its time to start dealing with some scaling issues.
If I'm going to give a novice PHP'r tips it would be along the lines of thinking about using a good stable framework.
For setting the .ini setting though, check out http://www.php.net/ini.core#ini.sect.performance
Thanks for your response, though.