There are a bunch of android versions of this game with asynchronous multiplay:
SCRABBLE Free: the official scrabble app. Words With Friends: one of the more popular. Wordfeud: my favorite, nickname j13u11fr09. Feel free to start a game with me, though I can't gaurantee I'll always be able to take my turn quickly and you'll probably kick my butt...
There are a ton of others, but these seem to be the biggest.
Droidippy is a good implementation of Diplomacy for android phones with a web interface also available. Long press and choose move, support, hold, or convoy. Messages to players and group chat as well as anonymous chat. Not a lot of variants but well worth the trouble and easy to use with pinch to zoom.