If you have a Google Toolbar you may want to add a Nutrition Data Button. If you go to the link you'll find an explanation of how to add the button and how to use the button.
I resisted adding the Google Toolbar but once I did I was glad. Just the highlight feature that finds words on a web page and highlights them is huge time saver when you are searching for specific information.
A nice feature of the Nutrition Data button is that it links to the ND Target Map which provides input as to where a particular food fits, in regard to calories, nutrients and how filling the food is.
Should you not have nor desire to install the Google Toolbar , my favorite site for good nutritional information is the USDA Database. Once you get the hang of using it you'll find it an invaluable aid.