If you're using the nightlies (the new 3d api), you can use skeleton animations. Although it's not in the stable release yet, it's fully functional afaik. Keyframed animations (like md2) is not supported (yet), but skeleton animations performs well enough (bone animations and gpu skinning). Ofcourse this only works with gles20 enabled.
Loading an animated model is basically the same as loading a still model, which it described here:
http://blog.xoppa.com/loading-models-using-libgdx/. If you're new to the 3d api, you probably want to go through the other tutorials on my blog as well. TL;DR: Don't forget to include animations when exporting to FBX, convert using fbx-conv to .g3db/.g3dj and load using AssetManager or G3dModelLoader.
You can use AnimationController to animate your model:
https://github.com/libgdx/libgdx/blob/m ... oller.java. Examples can be found in the tests
https://github.com/libgdx/libgdx/tree/m ... /tests/g3d, e.g. SkeletonTest:
https://github.com/libgdx/libgdx/blob/m ... nTest.java or Animation3DTest (which also includes blending animations):
https://github.com/libgdx/libgdx/blob/m ... DTest.java.
See it in action over here:
Single model:
http://www.youtube.com/watch?v=semWZ_gdXTcMultiple models:
http://www.youtube.com/watch?v=vdXNZ_Nz9IsSkeletonTest:
http://www.youtube.com/watch?v=8E0gtpBTfA0Animation3DTest:
http://www.youtube.com/watch?v=LJOVdGI9TpE