It seems that the latest version of the application was released some time ago and it's compatible with OS 10.2 or higher. Because of this, you should be able to use it on your system. If you can't due to compatibility issues, try to find another program with same functionality. To do this, use the Mac Informer's database. I suggest to take a look at Crosshairs. According to the developer, this is compatible with OS 10.6 or higher.