http://www.google.com/mobile/goggles/#dc=gh0gg
Google Goggles is a form of visual search for a mobile phone. Open the app, take a photo of something (such as a book, landmark, logo, or store) and Google will instantly return information on that object. It's ideal for things that aren't easy to describe in words. Google Goggles works better with certain types of queries. Try taking pictures of books and DVDs, landmarks, logos, artwork, businesses, products, barcodes, or text.
For the best results when taking pictures, hold your phone in "left landscape" mode and press the on-screen shutter button with your right thumb.
Note: Google Goggles is currently available for Android devices running Android 1.6 and above. To see which version of Android you're running, go to Settings > About phone > Firmware version. Google has confirmed that Google Goggles will be available on iPhone and other platforms soon.
Tere is a short YouTube video demonstration of Google Goggles at http://www.youtube.com/watch?v=Hhgfz0zPmH4