Google’s instant site preview thumbnails was launched last November and now it is available on mobile browsers too.
To use Instant Previews on your mobile device, do a search on www.google.com and tap on the magnifying glass icon next to any search result. Available on Android (2.2 & above) and iOS (4.0 & above) devices, clicking this icon allows you to get a visual idea of the link you’ll be clicking.
Instant Site Previews for Mobile video demo from Google below.