This plugin adds Spotlight ™ like live search with an ajax popup to 
the default search box. See the screenshot.
It can be used as a widget or directly as a PHP call in the theme.
The Live Search Plugin is heavily based on John Nunemaker’s 
<a href="http://www.wp-plugins-db.org/plugin/addicted-to-live-search/" rel="nofollow ugc">Addicted To Live Search</a>.
<h4>Changelog</h4>
<ul>
<li>1.4.7 Fix by Tony for “With mouseover on result in IE, there is no background image or color”.</li>
<li>1.4.6 Added livesearchpopup_resultsbox(width) to put the popup below a search box of your choice, e.g. from a theme.</li>
<li>1.4.5 Do not initialize if no livesearchpopup_results is found. In contrast to the original live search this plugin does not make sense without the popup anyway. This fixes a JavaScript bug in IE7.</li>
<li>1.4.4 Use wpurl instead of siteurl to allow installations of WordPress at different addresses (thanks to Draco)</li>
<li>1.4.3 Use <?php instead of <? in live-search-popup.php</li>
<li>1.4.2 Force update script to update the plugin.</li>
<li>1.4.1 Switched to the_post instead of the deprecated wp_start().</li>
<li>1.4 Finally permalinks work together with this plugin. In addition a “Show all” links was added at the bottom for the case that there are more posts than shown in the popup (thanks to Marco Luthe).</li>
<li>1.3.4 Moved the placeholder and autocomplete attributes of the search box to JavaScript as they are not XHTML valid (thanks to Marco Luthe)</li>
<li>1.3.3 Added some print commands in front of get_bloginfos (thanks to upekshapriya who noticed that)</li>
<li>1.3.2 Force update script to update the plugin.</li>
<li>1.3.1 Relative paths in css to allow installation which are not at the domain root.</li>
<li>1.3 Fixed behaviour for change and blur events of the search box. This fixes the “click-through” bug.</li>
<li>1.2.1 Updated to reflect that it works with 2.3 as well.</li>
<li>1.2 Bugfixes</li>
<li>1.1 Bugfixes</li>
<li>1.0 First release</li>
</ul>

Live Search Popup

Spotlight (tm) like live search with an ajax popup

nchankov

This plugin adding autocomplete functionality to search input field. It is using core jQuery library as well as 
autocomplete jquery plugin from http://www.pengoworks.com/workshop/jquery/autocomplete.htm
This plugin requires zero configuration, but since version 1.2.0 there is admin screen where you can enable the extra ‘number of matches’ next to each option and other goodies. 
You just need to activate and it’s ready to be used in the blog. The plugin is tested with WordPress 2.6.5, but until there aren’t big core changes, it sould work for all future releases. I don’t have 
information if this plugin will work with older versions of WordPress, but for sure it is working with 2.6.x. The last version 1.2.0 is tested on WP 2.7.1.
New in 1.3.5: When it’s selected to display posts and/or pages and the autosubmit is ON, then when the user clicks on the selected row it will go directly to the post or page url. This way user are skipping one step. The change affect only pages and posts. Categories and tags behave as now.
New in 1.3.0: Added result type option in admin. From now on you can choose which type of results will be displayed.
New in 1.2: This version could display number of matches found in the blog.
New in 1.2.1: Small fix for table prefixes and adding autosubmit once the item from the list is selected.
I would appreciate if you write an review/post in your blog with a link to my page: <a href="http://nik.chankov.net" rel="nofollow ugc">nik.chankov.net</a>. 
Thanks!
<h3>Thanks to</h3>
<ul>
<li><a href="http://nik.chankov.net" rel="nofollow ugc">My Self 🙂</a></li>
<li><a href="http://jquery.com" rel="nofollow ugc">jquery.com</a></li>
<li><a href="http://www.pengoworks.com/workshop/jquery/autocomplete.htm" rel="nofollow ugc">jQuery Autocomplete Plugin</a></li>
<li><a href="http://csixty4.com/" rel="nofollow ugc">Dave Ross</a> for the hint with name selector 🙂</li>
</ul>

Autocompleter

Adding autocomplete functionality to the blog search input field. The values provided are the tags and categories used in the blog.

Live Search Popup vs Autocompleter