[AND_REY]

Вот как то так:

Код:

procedure TForm1.Button1Click(Sender: TObject);
var
 i: Integer;
begin
For i:= 0 to Form1.ComponentCount - 1 do
 if Form1.Components[i] is TEdit then
  (Form1.Components[i] as TEdit).Text := ' ';
end;