WindowSpy

WindowSpy is a Free Portable application that can display window information for any window the mouse is hovered over. Commonly referred to as a HandleSpy or VBSpy program, Window Spy displays the Current Handle, Current Class, Current Text, Current Size, Parent Handle, Parent Text and Pixel Color of the select Window. This information can then be used within the Win32 API to control the application or program.
WindowSpy Screenshot

Download here