I'm using "Visual Leak Detector" for Visual Studio. VLD is open source and works fine!
Is surly better than watch the process manager

http://vld.codeplex.com/

A simple include in main.cpp is all you have to do. Every memory leak will be visible...

#ifdef _DEBUG
#define _ENABLE_VISUAL_LEAK_DETECTOR
#endif // _DEBUG
#ifdef _ENABLE_VISUAL_LEAK_DETECTOR
#include "vld.h"
#endif // _ENABLE_VISUAL_LEAK_DETECTOR