For those of you interested in developing plugins for WordPress, Mark Jaquith has whipped up a screencast (ala RoR) that does a great job of providing prospective WP developers a leg up in writing WP plugins. Very cool.
For those of you further along the developer pathway, be sure to check out Mark’s nigh-comprehensive list of WordPress plugin hooks. There’s a lot of stuff there that I never would have known about, shy of that very handy list.