Move Windows by holding Alt and clicking (and holding) the left mouse button anywhere in the window.

AltMouseWindowMove.ahk

; Move Windows by holding Alt and clicking (and holding) the left mouse button anywhere in the window.
; You'll need http://www.autohotkey.com to use this script

LAlt & LButton::
CoordMode, Mouse  ; Switch to screen/absolute coordinates.
MouseGetPos, EWD_MouseStartX, EWD_MouseStartY, EWD_MouseWin
WinGetPos, EWD_OriginalPosX, EWD_OriginalPosY,,, ahk_id %EWD_MouseWin%
WinGet, EWD_WinState, MinMax, ahk_id %EWD_MouseWin%
if EWD_WinState = 0  ; Only if the window isn't maximized
	SetTimer, EWD_WatchMouse, 10 ; Track the mouse as the user drags it.
return

EWD_WatchMouse:
GetKeyState, EWD_LButtonState, LButton, P
if EWD_LButtonState = U  ; Button has been released, so drag is complete.
{
	SetTimer, EWD_WatchMouse, off
	return
}
GetKeyState, EWD_EscapeState, Escape, P
if EWD_EscapeState = D  ; Escape has been pressed, so drag is cancelled.
{
	SetTimer, EWD_WatchMouse, off
	WinMove, ahk_id %EWD_MouseWin%,, %EWD_OriginalPosX%, %EWD_OriginalPosY%
	return
}
; Otherwise, reposition the window to match the change in mouse coordinates
; caused by the user having dragged the mouse:
CoordMode, Mouse
MouseGetPos, EWD_MouseX, EWD_MouseY
WinGetPos, EWD_WinX, EWD_WinY,,, ahk_id %EWD_MouseWin%
SetWinDelay, -1   ; Makes the below move faster/smoother.
WinMove, ahk_id %EWD_MouseWin%,, EWD_WinX + EWD_MouseX - EWD_MouseStartX, EWD_WinY + EWD_MouseY - EWD_MouseStartY
EWD_MouseStartX := EWD_MouseX  ; Update for the next timer-call to this subroutine.
EWD_MouseStartY := EWD_MouseY
return