Example AutoHotkey script that essentially makes Windows act like OS X Lion (significantly, it inverts the scroll direction of the trackpad)

AutoHotkey.ahk

; Increase maximum hotkeys (needed for scrolling to work)
#HotkeyInterval 250

; Alt-3 for Hash/Pound
!3::
Send {#}
Return

; Invert scrolling direction (OS X Lion behaviour)
WheelUp::
Send {WheelDown}
Return

WheelDown::
Send {WheelUp}
Return

WheelLeft::
Send {WheelRight}
Return

WheelRight::
Send {WheelLeft}
Return

; Cmd-X, C and V for cut, copy and paste
#x::
Send ^x
Return

#c::
Send ^c
Return

#v::
Send ^v
Return

; Cmd-A for 'select all' in some programs
#a::
Send ^a
Return

; Cmd-F for 'find' in some programs
#f::
Send ^f
Return

; Cmd-S for 'save' in some programs
#s::
Send ^s
Return

; Cmd-Z for 'undo' in some programs
#z::
Send ^z
Return