EasyHook - The reinvention of Windows API Hooking
WinAPIOverride - WinAPIOverride : This software allows you to monitor and/or modify any function of a process for any calling convention (stdcall or cdecl)
HookInjEx - How to inject code into another processes address space, and then execute it in the context of this process.
Deviare API Hook - Deviare is a professional open source hooking engine for instrumenting arbitrary Win32 functions, COM objects, and functions which symbols are located in program databases (PDBs).
madCodeHook - "madCodeHook" offers everything you need to hook code (mostly APIs).
API Monitor - API Monitor is a software that monitors and displays API calls made by applications and services. Its a powerful tool for seeing how Windows and other applications work or tracking down problems that you have in your own applications