Computer Status is a free and useful Dashboard widget that will allow you to track your computer's status.
Computer Status tracks the Internet In and Out, the Disk Activity and the CPU Usage with beautiful gauges.
Computer Status allows you to do all that from the comodity of your Dashboard. During the installation process it will integrate to your Dashboard and can be easily managed through the default widgets panel.
To learn more about your Dashboard's behaviour you can access the Apple support page HERE.