Maybe you already heard of this program, but it's not been used very much (or in a good way), so I was hoping this would help. :D
Animaki is a program designed to make really smooth pixel animations with. (of course it just makes things easier, it's not magic) There are various ways the program helps you to reach that goal:
-You can see the animation directly while you are drawing.
-Onion skin (so you can see the next or previous frame while drawing)
-You can change the speed of every frame, so with fast movements some frames can be shown very short, to create the fast effect better.
-You can see all frames on a row on the bottom.
-There is this skeleton layer. That means you can easily create a skeleton with vectors, move the body parts and test your movement in just a few minutes. Easier than drawing every frame. This is NOT rigged animation! You have to draw over the skeleton layer agian if you're satisfied with the movement.
And there is much more to make pixeling easier!
I hope you want to try it out and even use it! Here is the demo: http://www.deviantart.com/users/outgoing?http://www.oekaki.nl/animakidemo.html
And if you like it, you can register on oekaki.nl and start animating with the "Create a drawing or animation" button on the homepage! (don't worry, people only see your work if you decide to publish it)
Here are some examples created with animaki and the skeleton mode:
And a tutorial:http://wezenbeesje.deviantart.com/art/Using-skeleton-mode-in-Animaki-335308411
But you can draw without using the skeletonmode too of course. Here are examples of drawn by hand animations:
Tell others about this too! The programmer did a lot of work on this, so it would be nice to return the favor back.