for making the android app we use android mode of processing.
For hardware, i always choose arduino. here i have a Freeduino ADK from embedded market. for the communication since ADK is not that well developed for processing yet i am using ADB, which works for android OS as low as 1.6(i think).
also , i used a program that is a slider color chooser and then the same color goes to the rgb led.
the hardware can also be an arduino board with a host shield(i havent tried it, i just have a freeduino adk but it should be compatible)
we will start with making an android app on processing, then making it ready for adb, then make a compatible code for hardware and then sit back and enjoy the coffee.
Step 1: APP Making
this site does all the work for me, but keep in mind, the android version of your device and API 10 must be installed otherwise you are gonna have error my friend.
before, install the latest processing version if you don't have it. i am using 2.0b7 but 8 should not be a problem.
make the simple program, run it, then run it on your device and see that it sticks!