The National Agricultural Statistics Service updated their site to include a whole host of new ways to get their data, including a fancy new mapping service. The latest data I could find on their map was 2002, but you can really get at what you want pretty easily, either map or table form. One note is that their maps are in SVG format, which is an extenstion put out by Adobe. It allows for some pretty cool dynamic quering of data but it does require a plugin. If you’re into US agricultural statistics, the site is definately worth a look. Here’s the direct link to the site.