ScoreLoop is available for Android platform.
You can use ScoreNinja too. ScoreNinja offers an easy way to implement global scores but requires to view your score in the ScoreNinja application.
Otherwise Cocos iphone provides a global score with CocosLive. You can use CocosLive.net or use your own GoogleApp Engine VM. CocosLive is not available on Android platform but the protocol is REST with JSON and can easily be ported.
My current solution is CocosLive for Android and iPhone with my own VM but i will use ScoreLoop in my next game for social network integration.