There are many good books you can buy on animation but very few free books.
Preston Blair had a site some time back and you were able to access most of his first book but its only available now via the wayback machine . These days its getting harder to find good educational books on the web. I will endeavor to find all manner of good tutorials and articles to help bring out the animator in you. While surfing around I have found the book below. I suggest you download it for your personal library as it will undoubtedly be a great touchstone in future years.