I have not set this up myself here at DH (I have built and deployed wuftp at other sites), but I think it will work here with a URL of the format you describe.
When you set up the permissions, make sure you create a read-only server. If you want to permit uploading of files, I suggest you follow the guidelines in the wiki (an upload only directory, and you move files to public areas). Monkeyboy included a link to the article a few posts back.
An "open" anonymous ftp server can become a warez site before you can say "Why is my account disabled?"