<form action="ВАШ САЙТ " id="cse-search-box">
  <div>
  <input type="hidden" name="cx" value="partner-pub-3099497969485291:6e32g8cb9j0">
  <input type="hidden" name="cof" value="FORID:10">
  <input type="hidden" name="ie" value="windows-1251">
  <input type="text" name="q" size="31">
  <input type="submit" name="sa" value="Поиск">
  </div>
</form>
<script type="text/javascript" src="http://www.google.ru/cse/brand?form=cse-search-box&lang=ru"></script>

<div id="cse-search-results"></div>
<script type="text/javascript">
  var googleSearchIframeName = "cse-search-results";
  var googleSearchFormName = "cse-search-box";
  var googleSearchFrameWidth = 800;
  var googleSearchDomain = "www.google.ru";
  var googleSearchPath = "/cse";
</script>
<script type="text/javascript" src="http://www.google.com/afsonline/show_afs_search.js"></script>