Google engineer, Josh Redstone, posts to the Google Blog that they have made some improvements to the mobile web version of Froogle including the ability to sort results by price. Additionally, a mobile web version of Froogle is now available for the UK.
If you do not have a mobile browser that can access the new service, Froogle is also available via SMS in the US and UK. Smarter.com via SMS is another mobile service that allows you to compare prices.