Google instant popular search feature in desktops is now available for mobile phones(Android and iphone).
Google launched Instant search for desktops in september and have hinted about the mobile version will be released soon.
Concept behind Instant search
When you start typing the search query Google will predict the keyword and will dynamically load the webpage with asynchronous response (AJAX).The page will reload as many times as the search engine predicts your query.
Practically the instant searching option decreases the search time by seconds, though involve lot of data traffic.As you type the query, the request is sent to google prediction engine frequently which incurs data traffic.As this is very common on computers it wont trouble with the speed.
When it comes to mobile the data traffic is important.Instant search works fine when used on 3G and wi-fi.
This feature currently works on Android 2.2(froyo) and iOS4 in the US.
See what is google Instant