Someone on the SharePoint team took some time and built a VERY cool application for viewing ULS Logs. It lets you filter by any of the ‘fields’ in the log and format certain lines based on filter criteria.
Of course it lets you point the viewer at any ULS log file but it even lets you stream in the live ULS Log activity as it is happening and have it color code lines on criteria you determine.
If you find yourself looking at ULS logs for any reason then you will want to download this application
Get it here: http://code.msdn.microsoft.com/ULSViewer