Indicator-keylock is one of those tiny but extremely useful applications. Like the name says, it's an appindicator for viewing the status of the keyboard lock keys for machines which don't have keyboard LEDs like netbooks or even laptops. That means that you can quickly see if Caps Lock, Num Lock or Scroll Lock is turned on/off even if your machine doesn't have a keyboard LEDs to indicate this.
To install Indicator Keylock in Ubuntu, simply use the following commands:
sudo add-apt-repository ppa:tsbarnes/indicator-keylock && sudo apt-get update sudo apt-get install indicator-keylock
Once installed, start it by pressing Alt + F2 and then entering: "indicator-keylock".
Indicator Keylock also comes with Mono, Elementary and Humanity icons which you can install using the following command:
sudo apt-get install indicator-keylock-ubuntu-mono indicator-keylock-humanity indicator-keylock-elementary
Update: Indicator Keylock now also display NotifyOSD notifications on lock keys change!
Thanks to Timothy Scott Barnes for the tip!