I'm trying to figure a way for our small team to collaborate on to-do lists on projects and otherwise. We have tried Basecamp and a bunch of similar 'project management'/'collaboration' apps, but they seem to overkill for simple todo list sharing and management. We like Remember The Milk, but it is good only for individual lists.
Any ideas on a free/cheap alternative that's simple and just powerful enough to keep a small team of designers/developers productive?