function DesktopColor(const x,y: integer): TColor; 
var
  c:TCanvas;
begin
  c:=TCanvas.create;
  c.handle:=GetWindowDC(GetDesktopWindow);
  result:=getpixel(c.handle,x,y);
  c.free;
end; 
 
procedure TForm1.Timer1Timer(Sender: TObject); 
var
  pos: TPoint;
begin 
  GetCursorPos(Pos);
  Panel1.Color:=DesktopColor(pos.x, pos.y);
end;