API Tracer Level One
- http://www.geocities.com/ekhirin/
- Trap functions in DLL under Windows NT/2000/XP. Trapping engine is not limited in trapping DLL exports only and can trap any function, which address will be passed to it. [Freeware]
GDB: The GNU Debugger
- http://sources.redhat.com/gdb/
- Allows debug programs written in C, C++, and other languages, by executing them in a controlled fashion, and printing their data, on a wide variety of UNIX and non-UNIX systems.
SmartInspect
- http://www.gurock.com/products/smartinspect/
- A logging tool for debugging and monitoring .NET, Java and Delphi applications. Includes various logging libraries and a graphical viewer application. Site includes screenshots, tour, articles, and details of features. [Commerical, with free trial]