type TShowForm=Function (AHandle:THandle;ACaption:Pchar):Boolean;Stdcall;
var
mainfrm,DllForm:THandle;
ShowForm:TShowForm;
....
....
begin
mainfrm:=GetModuleHandle(dllform.dll');
// mainfrm:=application.Handle;
DllForm:=LoadLibrary(dllform.dll');
if DllForm <>0 then
begin
@ShowForm:=GetProcAddress(DllForm,'ShowForm');
ShowForm(mainfrm,'dllform');
end