Cocos2dx is the C++ implementation of Cocos2d. Even though it is C++ and cross platform it still uses plists. There are probably a lot of tools out there that can help you create these sprite sheets. I am currently using SpriteHelper which has export settings specifically targeting Cocos2D-X. I used to use Texture Packer for Cocos2D because it has a nice PVR viewer.
The main reason i am using SpriteHelper is because of Level Helper. Level Helper looks like it has a lot of potential.