I have provided sample project with the implementation code. I downloaded the original code from somewhere in Cocos2d-x forums and modified it properly to work with Mac OS X. All you have to do, is to add files from cocos2dx/keyboard_dispatcher to your XCode project, then put following in your CCLayer inheriting class:

[code language=”cpp”]
class HelloWorld : public cocos2d::CCLayer, public cocos2d::CCKeyboardDelegate {
…
virtual void keyDown(int key);
virtual void keyUp(int key);
}

bool HelloWorld::init() {
…
CCDirector::sharedDirector()->getKeyboardDispatcher()->addDelegate(this);
}

void HelloWorld::keyDown(int key) {
CCLog("%d pressed", key);
}

void HelloWorld::keyUp(int key) {
CCLog("%d released", key);
}
[/code]

If you are having some sort of difficulties with the code, please leave a comment.