Here is a custom TEdit that will tab to the next control when the user hits the <ENTER>

unit Ems;

interface

uses
  SysUtils, WinTypes, WinProcs, Messages, Classes, Graphics, Controls,
  Forms, Dialogs, StdCtrls;

type
  TEMS = class(TEdit)
  private
    { Private declarations }
  protected
    { Protected declarations }
  public
    { Public declarations }
     procedure KeyPress(var Key: Char); override;
  published
    { Published declarations }
  end;

procedure Register;

implementation

procedure Register;
begin
  RegisterComponents('Samples', [TEMS]);
end;

procedure TEMS.KeyPress(var Key: Char);
begin
  if key = #13 then begin
    key := #0;
    PostMessage(self.parent.Handle, WM_NEXTDLGCTL, 0, 0);
  end
  else inherited Keypress(key);
end;

end.