One really helpful link that one of my advisors gave to me was from an article that Peter Broderick wrote about "Maximizing Distribution."
Broderick emphasizes the importance of creating a web presence and reaching the core audience before the project is released:
During the filmmaking process, the filmmakers will have one to three years to learn how to reach their core audience most effectively. They will also have time to create an effective Web presence. This will enable them to build a valuable mailing list as they are creating awareness for their film within the target.