Roll your own WP plugin

http://paininthetech.com/2009/10/23/creating-a-wordpress-plugin

Backup and restore WP

http://www.quickonlinetips.com/archives/2009/10/backup-restore-wordpress-database/

WP security plugins

http://speckyboy.com/2009/09/22/20-powerful-wordpress-security-plugins-and-some-tips-and-tricks/

Basic tricks for WP

http://lifehacker.com/5365600/the-beginners-guide-to-tricking-out-your-wordpress-blog

Two-factor authentication for WP

http://www.howtoforge.com/secure-your-wordpress-blog-administration-with-two-factor-authentication

Must-have WP plugins

http://www.quickonlinetips.com/archives/2009/08/must-have-wordpress-plugins/

WP with jQuery tutorials

http://speckyboy.com/2009/08/06/30-tutorials-combining-both-wordpress-and-jquery/

Handle short URLs with WP plugins

http://www.quickonlinetips.com/archives/2009/07/shorten-url-wordpress-plugins/

WP security plugins

http://www.quickonlinetips.com/archives/2009/07/wordpress-security-plugins/

Useful WP hacks

http://www.instantshift.com/2009/06/15/22-mixed-quality-wordpress-hacks/

WP as CMS

http://www.noupe.com/wordpress/wordpress-cms-plugins.html

Time saving WP plugins

http://sixrevisions.com/wordpress/10-wordpress-plugins-guaranteed-to-save-you-time/

WP theme collections

http://www.smashingdownloads.com/2009/05/28/13-awesome-collections-of-free-wordpress-themes/

Clean free WP themes

http://speckyboy.com/2009/04/20/40-stylish-minimal-and-clean-free-wordpress-themes/

Attractive WP themes

http://www.hongkiat.com/blog/41-great-looking-free-wordpress-themes/

WP templates

http://www.tutzone.org/2009/02/free-wordpress-templates.html