try this (I trust you know enough to edit this to exactly what you want)
search.html:
Code:
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
<head>
<title>Untitled Document</title>
<meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1">
</head>
<body>
<table width="24%" height="60" border="1">
<tr>
<td bgcolor="#d5d8df"><font color="3a357c"><U>Search this site or google</U></font><BR>
<form name="search" method="get" action="redirect.php">
<input name="word" type="text"><br>
<input name="location" type="radio" value="0" checked>this site
<input name="location" type="radio" value="1"> google
<input type = "submit" value = "search">
</form></td>
</tr>
</table>
</body>
</html>
------------------
redirect.php
Code:
<?php
$word = $_GET["word"];
$site = $_GET["location"];
if($site == 0)
{
$term = "&as_sitesearch=yoursite.com";
}
else
{
$term = NULL;
}
echo "<META HTTP-EQUIV=\"Refresh\"
CONTENT=\"0; URL=http://www.google.com/search?as_q=$word$term\">";
?>