OS X :: Set Up Direct Download From Computer?

I'm running 10.6, and I would like to make my computer such that a friend (not on my local network) can directly download a large file from my computer. I would like to set this up in such a way that my friend will only be able to access a single directory (the Shared folder, for instance). Essentially, I want her to be able to download a file from my computer without giving her access to anything else, and without having to give out any sensitive information. I attempted to search, but as I'm not facile with the terminology, I didn't find an answer.