WordPress Google Search is a plugin by that easily setup a full text site search powered by Google.
WordPress Google Search Results Page
Normally to setup a Google Custom Search on your site you have to sign up on Google and create the search index. This plugin will do it automatically using Google’s Linked Custom Search Engines.
Works with any WordPress Theme
No need to setup a Google Custom Search
No Google account required
Search results show up on the default search result page.
Just add the “Google Site Search” widget to your theme.
Does not replace the default WordPress search. It runs along with it. Use both if you want.