This seems like a good app to me...

There’s no doubt that the iPhone platform has led to a huge torrent of great applications, and the Seasons iPhone application is a perfect example of that. The Seasons application will tell you what fruits, vegetables, lettuces, herbs, fungi and nuts are in season in your local area. By eating local and seasonal foods, you massively reduce the air miles on food produce, since the foods you eat are sourced from your local area rather than imported from another country.