Chess Time is the best multiplayer multiplatform that I know of right now. Sadly chess with friends isn't on android like others have said. If you're looking for an android platform multiplayer chess app, might I suggest Genesis Chess.
https://market.android.com/details?id=com.chess.genesis&hl=en
It's a beta app that my brother and I have created, you might like it. Although currently we haven't started making an iphone client.
