What good free and widely used tools are there for editing 2D skeletal animations? Preferably, one that allows me to write custom animation exporters.
One pretty good indie tool that I know of Demina, but it's not ideal. It doesn't allow you to export the data as you want (although, it is open source, so you can change that) and I find it clunky in how you edit individual joints.
What other tools would you recommend?