NOTIFYICONDATA nid;
HICON hIcon;

INT_PTR APIENTRY MainProc(HWND hwnd, UINT msg, WPARAM wParam, LPARAM lParam);

WINAPI WinMain(HINSTANCE hInstance, HINSTANCE hPrevInstance, LPSTR lpCmdLine, int nCmdShow)
{ //Создаём окно расписанное в Res.rc
  int ret = DialogBox(GetModuleHandle(NULL), MAKEINTRESOURCE(ID_MAINDIALOG),NULL,(DLGPROC)MainProc) ;
  return ret;
}
//---------------------------------------------------------------------------
INT_PTR APIENTRY MainProc(HWND hwnd, UINT msg, WPARAM wParam, LPARAM lParam)
{
  switch (msg){
    case WM_INITDIALOG:
            hIcon = LoadIcon(GetModuleHandle(NULL), "MYICON");
            nid.cbSize = sizeof(nid);
            nid.hWnd = hwnd;            
            nid.hIcon = hIcon;
            lstrcpyn(nid.szTip, "Пример трея", sizeof(nid.szTip)/sizeof(nid.szTip[ 0 ]));
            nid.uFlags = NIF_ICON | NIF_TIP | NIF_MESSAGE;
            Shell_NotifyIcon(NIM_ADD, &nid);
            break ;
    case WM_CLOSE:
            Shell_NotifyIcon(NIM_DELETE, &nid);
            EndDialog(hwnd,  0 );
            break;
  }
  return FALSE ;
}

case WM_INITDIALOG:
  UINT s_uTaskbarRestart = RegisterWindowMessage("TaskbarCreated");
  //.........
  break;

default: 
  if(msg == s_uTaskbarRestart)  
     AddTaskbarIcon(hTrayIcon);
}