I originally installed Eclipse on Ubuntu 10.04 and have since migrated to 12.04.1. I originally used Eclipse 3.5 (Galileo) and Eclipse 3.7 (Indigo). And I used Arduino v22 with a DueMilaNove?. I have not double-checked that the instructions below are still working under 10.04, Galileo and/or Indigo, and with the Arduino v22. There may be differences in those configurations you will have to do on your own.
Install the prerequisites
These are instructions on installing the basic components to compile and Arduino from Eclipse. The ATMega? microprocessors are part of the AVR family and so require the AVR compiler to run. Eclipse is cross-platform, cross-toolchain IDE. The AVR plugin is used inside of Eclipse to run the AVR compiler and create binary images for the Arduino.
The simplest project is to blink the Arduino's on-board LED. Compiling and uploading this project will test that Eclipse, the AVR plugin, Arduino toolchain, the AVR compler and the project's the compiler/linker settings are all correctly set up, plus it also shows you the common steps you use when you develop a project on the Arduino.