Hoo WinTail is a real-time log monitor & viewer for Windows like the UNIX tail -f utility. It can capture and display OutputDebugString (Windows Debug API) and TRACE (MS Visual C++ Debug Macro) output as well.
Tail4Win is used to monitor changes to files and display the changed lines in realtime. It is very usefull for monitoring log files of applications - e.g. Apache's logs or IIS's logs. It can capture and display OutputDebugString / TRACE.