I wrote FotherFood to help generate our grocery shopping list. It is a tiny open-source web-app written in Javascript.

You can see a demo at http://www.tomfotherby.com/Websites/Fotherfood/Fotherfood/index.html.

For what I'm currently working on, see the ToDo list

Feature List for version 0.1 (released 14/Nov/08):

1. Buttons to add recipes to the shopping list (initial list of 5 recipes).
2. Buttons to add regular shopping items to the shopping list (e.g. milk, bread, eggs, etc).
3. Tracks the number of portions of each recipe in the shopping list.
4. Each recipe has a "More Info" drop-down icon to display recipe details.
5. Identical ingredients are summed together in the shopping list
6. The shopping list is sorted alphabetically by ingredients
7. Print mode - Only shows what's in the shopping list (not every recipe).