OpenPop framework classes uses the property DefaultLogger.Log to obtain a logger where all logging information is sent to.
All loggers must implement the ILog interface:

/// <summary>
/// Defines a logger for managing system logging output  
/// </summary>
public interface ILog
{
    /// <summary>
    /// Logs an error message to the logs
    /// </summary>
    /// <param name="message">This is the error message to log</param>
    void LogError(string message);

    /// <summary>
    /// Logs a debug message to the logs
    /// </summary>
    /// <param name="message">This is the debug message to log</param>
    void LogDebug(string message);
}

You can change what logger the DefaultLogger.Log property points to be calling DefaultLogger.SetLog(...) as done below:

/// <summary>
/// Example showing:
///  - How to change logging
///  - How to implement your own logger
/// </summary>
public static void ChangeLogging()
{
    // All logging is sent trough logger defined at DefaultLogger.Log
    // The logger can be changed by calling DefaultLogger.SetLog(someLogger)

    // By default all logging is sent to the System.Diagnostics.Trace facilities.
    // These are not very useful if you are not debugging
    // Instead, lets send logging to a file:
    DefaultLogger.SetLog(new FileLogger());
    FileLogger.LogFile = new FileInfo("MyLoggingFile.log");

    // It is also possible to implement your own logging:
    DefaultLogger.SetLog(new MyOwnLogger());
}

Here is the custom implementation used:

class MyOwnLogger : ILog
{
    public void LogError(string message)
    {
        Console.WriteLine("ERROR!!!: " + message);
    }

    public void LogDebug(string message)
    {
        // Dont want to log debug messages
    }
}

If you just want to log to a file, you can use the FileLogger class.