BALLOONTIP برای EDIT

type 

  tagEDITBALLOONTIP = record

    cbStruct: Longword;

    pszTitle: PWChar;

    pszText: PWChar;

    ttiIcon: Integer;

  end;

type 

  PEDITBALLOONTIP = ^tagEDITBALLOONTIP;



const

  ECM_FIRST         = $00001500;

  EM_SHOWBALLOONTIP = ECM_FIRST + 3;



procedure TForm1.Button1Click(Sender: TObject);

var

  ebt: tagEDITBALLOONTIP;

  title, Text: Widestring;

  icon: Integer;

begin

  title := 'tooltip!!';

  Text  := 'in editbox :)';

  icon  := 1; //0,1,2,3

  with ebt do

  begin

    cbStruct := SizeOf(ebt);

    pszTitle := PWideChar(title);

    pszText  := PWideChar(Text);

    ttiIcon  := icon;

  end;

  SendMessage(Edit1.Handle, EM_SHOWBALLOONTIP, 0, Longint(@ebt));

end;

نقل از سایت TORRY
MSDN :
http://msdn.microsoft.com/en-us/library/bb761668(VS.85,printer).aspx

نکته مهم که جایی نبود. حتما از XPMAN استفاده کنید