What is a good online supermarket price comparisson?

[inneedofhelp]

I used to use cairo, which detailed both Safeway and Albertson's and others prices. Now it has changed and the shoplocal isn't really so good as it shows online internet prices (who buys milk online with s&h?).

Is there a good site that will show you prices for a specific type of item (example---chicken) at multiple different stores?