One of my favorite resources is the Tomorrow's Professor Listserv, maintained by Richard M. Reis, of Stanford University. Twice a week emails bring professional development resources to your inbox. Postings cover the nature of academia, preparing for and managing academic careers, teaching and learning, research, and more.
Better yet, all of the postings are archived, so new subscribers can read up on early posts. To subscribe to Tomorrow's Professor, send an email to: Majordomo@lists.stanford.edu with subscribe tomorrows-professor in the body of the email.