This is essentially an alternative to AHK's WindowSpy, I include it in my main script and start it using LButton & Esc::
The example screenshot below shows you what you'd see when hovering the mouse over Excel 2003, and gives you a good idea of what this script is for.
You can copy individual items by pressing the keys in brakets, for example, pressing V copies the ClassNN of the control under the mouse, and so on. To copy everything press the Alt key.
On the assumption that most of us are right-handed, shortcut keys have been chosen so that only the left hand is involved, thus leaving the right hand available for operating the mouse. If you are left-handed you'll probably want to choose keys from the opposite half of the keyboard.