Application that are running on local system include many important information such as login passwords and other sensitive credential, it is possible for an attacker to have all these details by reversing the software while it is running on the system.
Some programs are using encryption but you still can use oSpy to receive API application calls, oSpy will hook API calls and display process activity, after executing the application you start by capturing the targeted process to monitor, next you leave it sometime till it get some process calls, finally you stop it and it will display all logs.
The tool is very useful to capture instant messaging API such as MSN and Google talk while you can use it also to monitor malicious processes on your computer.
oSpy is an open source project so you can contribute and enhance overall functionality. While you can have more information at the official website.