From Byrne Consultancy:
Windows software developers can have multiple exception handling tools installed and are normally required to amend registry entries to swap between them. Debugger Selector changes that. Now, with Debugger Selector, the exception handling tools (for example Visual C++ or WinDebug) can be defined either in advance or when the exception occurs and Debugger Selector will route the exception to the developers chosen tool. In addition, Debugger Selector allows the developer to define exception handling functions (in DLL's) which can be used to pass the trap on to for processing. Debugger Selector can be used on Windows NT4.0 and above Debugger Selector is free to individual users (registration required). Corporate users are required to purchase an appropriate licence.