Various logs can be found here:
They can be read by opening a terminal (
Applications -> Accessories -> Terminal in Ubuntu 10.04, etc.) and typing:
(Use the space bar to go to the next page; type ‘q’ to quit.)
Most of the files in /var/log can also be viewed using Ubuntu’s Log File Viewer. In 10.04, this is found by navigating to
System -> Administration -> Log File Viewer from the taskbar. There is a menu listing the available logs on the left-hand side of the Log File Viewer; click on the name of a file to view it.