Have you ever noticed a mysterious system process that seems to be consuming resources but you can't get to the bottom of it?
If so, Sonar could be of use to you. Sonar is a security tool that provides real-time reporting of file changes on your hard drive. Chances are, if it's running on your system, Sonar will be able to monitor it. The nice thing about Sonar is that it shows in a click, exactly where the source of the file is. This is essential in rooting out malicious files or simply monitoring software you don't trust.
Sonar works via a very simple interface which enables you to turn 'listening' on and off. When you click to start listening, Sonar will look for processes running on your system. At first, Sonar does take a while to compile them all, although this shouldn't take more than 30 seconds. Once the processes are listed, you can click on them to see exactly where they're coming from and which application is responsible. You can flag those processes that you are suspicious of, enabling you to keep an eye on them more easily. When you're finished, simply stop Sonar listening.
Although Sonar was designed specifically to monitor Tiger, it has recently been upgraded to work with Leopard. The developer can't guarantee that it will work with the soon-to-be released Snow Leopard, however.
If you've ever felt a process is damaging your hard drive or find that your process monitor simply doesn't analyze deep enough, Sonar is your solution.