The Tofugu website provides a great mix of content about Japan including pop culture, traditional Japanese culture, history and more. Check out their Learn Japanese guide to find resources appropriate to your level.
Japanese Pod 101
You can create a free account with Japanese Pod 101 or subscribe to their podcast to listen to free lessons grouped by language level.
Easy Japanese with NHK
The NHK also provides free Japanese through their Easy Japanese program.
Jisho.org is a Japanese dictionary website. One of the most useful functions allows you to draw Japanese characters.
Apps, Add-on's and Software
Anki is a free flashcard app that allows you to make your own flashcard decks or download decks that other users have made. It's a great way to make decks targeting the vocabulary that's important to you.