http://wpajax.com/
I’ve heard of this book for a while, recently I found it could be downloaded as a free e-book, that’s so generous! Don’t hesitate to get your own copy!
Resources
Google Typography by Eric Alli
Just stumble upon Google Typography by Eric Alli, a plugin let users to change and customize fonts from Google Fonts for any WordPress themes.
Save a file from web into Media Library in WordPress
http://theme.fm/2011/10/how-to-upload-media-via-url-programmatically-in-wordpress-2657/
You could use download_url to grab a file from a given URL, then use media_sideload_image to save it into Media Library and attach to a post (optional).
Admin Column View for WordPress by Crowd Favorite
Admin Column View is a brilliant new tool to manage hierarchical posts (like Page) in WordPress. Check out this video to see the elegant UI, which was inspired by the OS X Finder.
WP Tweet News by Chris Lema
http://wptweetnews.com/
Chris built a WP news aggregator from his Twitter list.
Backbone.js And WordPress Resources from Peter Knight
http://www.peterrknight.com/backbone-and-wordpress-resources/
This is the most comprehensive resources I’ve ever seen for WordPress and Backbone.js.