I funded this awhile ago, and it was very relevant for a project I was working on, but if you guys are interested- the KickStarter has it discounted quite a bit:

http://www.kickstarter.com/projects/esotericsoftware/spine

I'm using it instead of flash for animating characters for my game, and it does a good job, as well as being lightweight.

They also have runtimes for libGDX, cocos2d, and since they made their goals, AS3, C#, javascript, ect.

Made by one of the two guys who are the main contributers of LibGDX.

Definitely more than worth it if you intend to ever use 2d skeletal animation in a project.

I spent a couple months writing a AIR program to convert flash XML files into easily read XML/JSON files, then loading them into my game, and it is still quite a ways off their app (That also includes the program to actually animate).


You can also buy it not off their website, but for a bit extra outside of the KickStarter(if you can't stand waiting 2 more days)
http://esotericsoftware.com/uncategorized/kickstarter-stretch-goals/