In the current 1.0 implementation, the SearchEkko plugin simply puts an expanded widget at the end of each post. It also adds a collapsed widget after the first paragraph on longer articles. The widget is only added to single-post pages, not your home page. You can get the SearchEkko plugin as follows:

• Search "searchekko" in the "Install Plugins" section of your WordPress Administration Panels. Then simply click the install button to add it to your blog, and activate it in the plugins list.
• Download it from the official WordPress plugins directory listing or locally, and copy the file to your webserver's wp-content/plugins directory. Then activate it in your plugins list. For more information, take a look at these instructions.

Also, you can modify the CSS of the widget as shown here.

Remember, the SearchEkko widget will only show up if you arrive at your web page from a search engine (Yahoo, Bing, or Google).