Mac OS X 10.5 Help
Viewing system messages
While your system performs tasks, it sends messages between applications, processes, and the operating system. Some of these messages are displayed, but most are not displayed because they can be too detailed and technical. If you are a programmer debugging software, or are troubleshooting a problem with a service technician, messages related to the problem may be located system logs. To view these messages you can use the Console utility located in the Utilities folder in the Applications folder.
For more information, Open Console, and then choose Help > Console Help.