Google API - Ajax Search Engine
Go to => http://code.google.com/apis/ajaxsearch/web.html
( These are the types of search engine APIs you can add )
All details of how you can add one to your say website/blog is given here
http://code.google.com/apis/ajaxsearch/documentation/
I tried out this at home with this one just to start with :
Example 1 : start.html
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN"
"http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<meta http-equiv="content-type" content="text/html; charset=utf-8"/>
<title>Hello World - Google AJAX Search API Sample</title>
<script src="http://www.google.com/jsapi" type="text/javascript"> </script>
<script language="Javascript" type="text/javascript">
//Here you are loading the API
google.load('search','1');
function OnLoad(){
//create a search control (which is used to create / control further searchers)
var sr1=new google.search.SearchControl();
//start adding searchers
sr1.addSearcher(new google.search.WebSearch());
sr1.addSearcher(new google.search.BlogSearch());
sr1.draw(document.getElementById('id1'));
//Start with initial search
sr1.execute("namrata khandeparkar");
}
google.setOnLoadCallback(OnLoad);
</script>
</head>
<body>
<div id="id1">Loading</div>
</body>
</html>
Try it out