The following method can be used save string messages out to log files.  In the code below I am using a couple class fields to establish the log file name.  These can be customized to meet your need.

  
public void Output(string message) {  
        if (_logFilePath != stringEmpty) {  
        string fileName = "LogFile";  
        if (_contentDatabaseName != string.Empty)  
            fileName += "_" + _contentDatabaseName;  
  
        fileName += ".txt";  
        string filePath = System.IO.Path.Combine(_logFilePath, fileName);  
        System.IO.StreamWriter sw = System.IO.File.AppendText(filePath); // Change filename  
        try {  
            string logLine = System.String.Format("{0:G}: {1}.", System.DateTime.Now, message);  
            sw.WriteLine(logLine);  
        } finally {  
            sw.Close();  
        }  
    }  
}

Cool eh?