Log Parser is a very powerful, free and versatile tool that provides universal query access to text-based data, such as log files, XML files, and CSV files, as well as key data sources on the Microsoft Windows operating system, such as the event log, IIS log, the registry, the file system, and the Active Directory directory service.
Becouse the command-line interface is not very intuitive, we have created Log Parser Lizard, a GUI tool for managing queries, exporting results to Excel, charts, etc… In addition I have added input filters for log4net file format (with support for regular expressions) and SQL server T-SQL queries. | 
