Yann Sionneau recently completed a port of JGroups to Android (2.1+). He took the 2.11 version of JGroups and removed classes which weren't available on Android, and changed some code to make JGroups run on Android.
The QR code for a demo app (based on Draw) is available at . Point a QR code scanner to it, download the app and run it on your Android based phone (I ran it on my HTC Desire). Then start Draw on your local computer, connected to the same wifi network as the phone. The instances, whether run on the phone or computers, should find each other and form a cluster.
It was cool to draw some lines on my HTC and see them getting drawn on all cluster instances as well !