www.withoutabox.com - The main website for film festival submissions. Be sure to verify important dates with the actual website for each film festival. Some film festivals do not use this site, while others use it exclusively. Whatever your film festival strategy, you'll most likely want to create an account on this site (it's free).
www.shortfilmdepot.com - This site is specifically for short films and has a strong international selection of film festivals. We created an account here.
http://www.filmfestivalsecrets.com/book/issuu/ - Chris Holland's ebook takes you through every step of the film festival process, with specific tips for short filmmakers. He runs a newsletter, http://www.filmfestivalsecrets.com/, where he profiles festival programmers and features other content touching on the film festival circuit. Chris also offers consultations for extremely reasonable rates (we plan to do this).
How Not to Make a Short Film - Roberta Munroe's book on short film tips based on her experience as a Sundance programmer. Roberta also offers consultations at her site, robertamonroe.com.
Chris Gore's Ultimate Film Festival Survival Guide - Great book on film festivals, festival strategy and marketing, and lists of top film fests in different areas.
Other sites I found helpful:
http://motion.kodak.com/US/en/motion/Education/News_And_events/filmTip.htm
http://www.fauxfilm.com/tips/ - Click on "Film Festival Submission Tips"
http://www.lavideofilmmaker.com/film-festivals/film-festival-tips-advice.html
http://videomaker.com/community/forums/topic/for-consideration-film-festival-tips
http://www.thefilmlot.com/articles/ARTsuccessfulshort.php
