still have trouble to load android SDK into Eclipse under Ubuntu. I have Ubuntu 64-bit version installed. In order to run 32-bit application, I need to install a few things.  There are problems installing Java JDK6, and then, I can't install Android plug-in to Eclipse.

In the end, I give up on Eclipse, and install Eclipse with Android plugin on Mac OS Lion. It has Intel Core i5, which is 64-bit processor.  This does the trick. 

This is my setup.  I run a java client code on Mac.  It runs an Android Emulator, which will send and take signals through wireless connection to a Dell running Ubuntu, which runs a C server code
and connects to a Arduino board with Xbee via USB cord.

The Arduino with Xbee will send a signal wirelessly to another Xbee, which is attached to a robotCar.

By sending a signal from Android Emulator on Mac, the robotCar can move accordingly.  Also,
when a barrier is encountered,  a signal will send back to,  a message will display on the Android Emulator on Mac.