API Monitor is a software that lets you monitor and control 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. 32-bit and 64-bit Alpha Versions are now available for download.
API Monitor 2.0
Current version supports 13,000+ API’s, 1,300+ COM Interfaces, breakpoints, memory editor and decoding of structures, unions, arrays, enumerated data types and flags.