Evitar que seu programa apareça na barra de tarefas

program Project1;

uses
  Forms, Windows,
  Unit1 in 'Unit1.pas' {Form1};

{$R *.RES}

var
  ExtendedStyle : Integer;
begin
  Application.Initialize;

  ExtendedStyle := GetWindowLong(Application.Handle, gwl_ExStyle);
  SetWindowLong(Application.Handle, gwl_ExStyle, ExtendedStyle or
    ws_Ex_ToolWindow and not ws_Ex_AppWindow);

  Application.CreateForm(TForm1, Form1);
  Application.Run;
end.