log4net

WeatherServices (local weather station pushed to personal messenger/web interface) is going to use .net web services. After looking for around at logging tools, log4net bubble to the top. Works very much like log4j. One bit of Windows nastiness, is that all the documentation says to give ASPNET write/modify access to the file you are going to log to. Unfortunately, IUSR_<MachineName> needs to have access also for a Web Service.

Other than that, seems like a very unintrusive tool.