Here is a simple utility I wrote to process the MOSS usage logs (when turned on at Central Administration >> Operations >> Usage Analysis Processing ). Sometimes it's useful to have alternate source for the user activity, than the usage reports offered in MOSS OOB through the Site Settings.
I have slightly modified the Parser class found at http://www.sharepointblogs.com/wpowell/archive/2007/06/22/moss-usage-log-processing-file-processing.aspx . The MOSSLogParser.exe utility loops through all log files and creates a single CSV file, ready for Excel pivot tables.
the syntax: MOSSLogParser.exe <start_path> <search_pattern>