<form action="https://ВАШ САЙТ" id="cse-search-box">  
  <div>  
  <input type="hidden" name="cx" value="partner-pub-2552537688454945:dg404m-yrp0" />  
  <input type="hidden" name="cof" value="FORID:10" />  
  <input type="hidden" name="ie" value="UTF-8" />  
  <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/coop/cse/brand?form=cse-search-box〈=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>