Dan Winter has created a really great tool to monitor the log-files in a SharePoint-farm. You can find his tool in the MSDN Code Gallery. You can use this tool for SharePoint 2007 and SharePoint 2010 installations. It has great filtering options so it’s really simple to find the needed information in the log-files.
What I’ve seen today while I was testing a while: the tool seems to have problems when it’s used on operating systems that are non-english. I’m from Germany, so we have a lot of installations running with Windows and SharePoint in our language. When I run ULS Viewer on such a machine, I get an error, when I open a log-file, or when I try to use the runtime-logging. It seems, as if ULS Viewer has trouble in this cases to read the datatime value in the log-file. If you read the comments on the homepage for this tool in the MSDN Code Gallery, I’m not the first, who has these problems.
Actually I’m testing, if it is an option to use a client machine running an operating system with an English language. Using this system, I would try to access the log-files using a file-share. I hope, that’s a solution for this problem.
Update: Using a machine running an operating system with an English language solves the problem. All you need to do in this case is to load the ULS file from an admin share of the SharePoint machine.