I'm using log4net and log4view (www.log4view.org). They have a TCP adapter that you can distribute as part of your application. You then use their client app to connect to your various applications and the log messages are displayed in real time.
It can monitor multiple logs at the same time - up to 255 if you but the commercial version (a measly $50).
It can also work with the RollingFileAppender.
They have a pretty powerful filtering UI so you can home in on what you want to look at.
