When Google Product Search for Mobile was launched, it was only for the iPhone and Android phones. Now, it's available for all internet-enabled devices in the US, UK, Germany and South Korea.
Additionally, Google Suggest, a query suggestion feature, has been added to Product Search for Mobile, but it is limited to iPhone, Android and Palm Pre phones in the U.S.
To use Product Search for Mobile, simply browse to google.com on your mobile phone and conduct a search. Then clcik on "Shopping results" to view products.
You an also access Product Search for mobile directly by browsing to www.google.com/m/products.