Some might be interested in this free pixel art animation course.
I just signed up for the course. Looks pretty awesome! I'll let everyone know how it is!
Some time ago I also backed a project on Indiegogo called Pixel-Logic, which aims to create a comprehensive book of pixel art tutorials. Unfortunately it's not all free right now, but they do have some really nice sections of the book that they release for free: http://pixellogicbook.com/
Once the book is complete, I believe they will be releasing the full book online for free.