Basecamp, a lovely organizational tool for groups that are working together on the web, now offers and ftp service for its paid plans, which I think makes it much more useful (you don't need your own ftp server).
New to Basecamp? In short: it's a great way to work together with a team of people on a projects that have lots of little deadlines. It's also nice for keeping track of personal projects. Great for freelancers and nonprofits for use as a private just-add-water network. It's not open source, and only the single-project plan is free, but it sure is easy to use. Go get some good done.