<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>