ToonBoom is one of the main animation programs out there. You can try using Photoshop too to make your images play in sequence. (If you are interested in 3d too, take a look at maya. on the autodesk website, they have free student version)
A good resource is DEFINITELY The Animator's Survival Kit. KNOW YOUR 12 PRINCIPLES OF ANIMATION (they are principles made directly from Disney). Also watch various animation. Disney movies are always good~ Youtube can provide good materials too.
Traditional 2D animation is done with a lightbox (Referring to old school disney days like Steamboat Willie). Basically draw on a piece of paper, and have the lightbox shine through the back, add another layer of paper and draw the next movement. Standard timing is 24 frames per second, basically drawing 24 sheets of paper to produce a second. Toonboom is used for your digital animation.
Steps to take if you're keen on doing animation: DRAW! Get to know human anatomy and how it moves. Look around your local area and sign up for animation school. Watch tutorials.
I think that's about it. Hopefully this helps~ Feel free to ask if you've to more questions