http://brian.brispace.net/2009/04/09/php-on-google-app-engine/

There's a link around the end of the comments to a sample app too.

http://www.smashingmagazine.com/2009/04/03/8-handy-tweaks-to-make-gimp-replace-photoshop/

http://www.wikivs.com/wiki/MySQL_vs_PostgreSQL
http://wiki.postgresql.org/wiki/Why_PostgreSQL_Instead_of_MySQL_2009

There's a bunch of stuff in the comments, everything from the old print '';var_dump();print '';
(with the added wrinkle of using ob_start then ob_contents, etc. in some incarnations) to an open-source project called Krumo that reminds me of that Javascript-based unobtrusive thing I journalled about a while back (i.e. http://defproc.co.uk/dpDebug2/)

http://sourcemaking.com/design-patterns/php

A list of wireframing tools, from free to expensive:
http://editorial.co.in/wireframes/wireframes.php

http://www.commandlinefu.com/commands/browse

http://stayupdate.com/stayupdate/10-online-resources-to-find-free-gimp-tutorials/308

Via http://smartbabesaresexy.blogspot.com/2009/01/top-5-free-internet-sites-for.html

http://www.1stwebdesigner.com/resources/45-sites-free-icons-and-psd-resources-for-web-design/

To save some time and to keep Google from having to pay loads of nickels to Mozilla as I look up various topics for interview-prep:

OOP
http://en.wikipedia.org/wiki/Polymorphism_in_object-oriented_programming
(GoF pattern examples: Adapter/Wrapper and Strategy patterns).

MySQL for Grown-ups:
=======================

For various reasons, MySQL has been undergoing a lot of development outside of MySQL AB (now part of Sun). This is meant to list some of the more important players/packages/etc.

http://blogs.sun.com/dups/entry/ideas_on_integrating_memcached_into

Read the comments too.