Installing ROS in Ubuntu 12.04 (Precise)

$ sudo sh -c 'echo "deb http://packages.ros.org/ros/ubuntu precise main" > /etc/apt/sources.list.d/ros-latest.list'
$ wget http://packages.ros.org/ros.key -O - | sudo apt-key add -
$ sudo apt-get update
$ sudo apt-get install ros-fuerte-desktop-full
$ sudo apt-get install python-rosdep
$ gedit ~/.bashrc

-- Add the following lines

source /opt/ros/fuerte/setup.bash
export ROS_WORKSPACE=~/fuerte_workspace/
export ROS_PACKAGE_PATH+=:~/fuerte_workspace/sandbox/

--

$ mkdir -p ~/fuerte_workspace/sandbox/ 
$ source ~/.bashrc
$ sudo rosdep init
$ rosdep update

--

Extra dependencies

$ sudo apt-get install ros-fuerte-joystick-drivers
$ sudo add-apt-repository ppa:joseluisblancoc/mrpt 
$ sudo apt-get update
$ sudo apt-get install libmrpt-dev mrpt-apps