If you're interested in Moodle development, you'll most likely want to visit and/or subscribe to Planet Moodle.
Planet Moodle collects and displays blog posts from Moodle developers and users around the world. Recent posts include an explanation by David Mudrak of how advanced grading methods in Moodle 2.2 was developed, white papers from Gavin Henrick on Moodle 2 themes and repositories, and a useful series of posts by Mike Churchward on converting Moodle 1.9 plug-ins to Moodle 2.
In addition to the RSS feed, you can be notified of new posts by following @moodle on Twitter.