Chess apps for kindle fire/android

My kids (girls 7 and 9) often end up waiting for the other to finish with some sort of activity.  I have a kindle fire and they love to play with it.  I'm hoping they will do more chess and less subway surfer.   I was wondering what chess apps people liked or disliked for their kids.

Newb chess is for ipad and my niece has that.  Its nice because it has different computer strengths that she can play against and gradually improve.  It also doesn't have allot of ads.  But I don't think its available for android or kindle.  

My kindle has a 4 g connection so there is some limited wireless available even when we are on the road.    

My 7 year old nephew loves solving easy mating puzzles using the puzzles app, iChess, that I developed! http://goo.gl/SenMe

If you have a collection of easy mate puzzles, you can load that in the app, or buy one from within the app.

Thanks  I will definitely check those out.