paste this code in ur site
<!-- Search Google --><center><FORM method=GET action="http://www.google.com/search"><input type=hidden name=ie value=UTF-8><input type=hidden name=oe value=UTF-8><TABLE bgcolor="#FFFFFF"><tr><td><A HREF="http://www.google.com/"><IMG SRC="http://www.google.com/logos/Logo_40wht.gif"border="0" ALT="Google" align="absmiddle"></A><INPUT TYPE=text name=q size=25 maxlength=255 value=""><INPUT type=submit name=btnG VALUE="Google Search"></td></tr></TABLE></FORM></center><!-- Search Google -->