Things you will need:
AutoIt v3
SciTE

Open scite. Copy and paste this script:

Code:
HotKeySet("z","jPos")

While 1
    Sleep(100)
WEnd

Func jPos()
    $jPos = MouseGetPos()
    MsgBox(0, "Mouse x,y:", $jPos[0] & "," & $jPos[1])
    
EndFunc
Save the script somewhere and name it whatever you want (I named mine getmouseposition).

Open autoit v3, browse to that script and open it.
Now whenever you press the key 'z', a pop up box will show your current mouse positions coordinates.

Of course there's the other method where you just drag the crosshair and it'll list the coordinates, but I prefer doing it this way instead.