Mircea suggested a lot of time ago that I could use HFS - he has been using it that time for a few file transfers and he was satisfied by it; just as he did, I downloaded it from snapfiles.com
To put it simple, the best thing about HFS is that you simply start it, add what you want to be downloaded/shared, give the link to a friend to download the file and when you're done, you simply close it. (there's no need to install anything; as I've already told you it's a simple solution - and it works; should you need a more complex solution, do install a complex server, like Apache for example)
So, since then I've been using HFS from time to time to transfer files between me and my friends.
Today I was forced to discover an exciting new feature of HFS: you can also use it for uploads. I followed the steps explained here and it worked just fine. (The problem was that at the other end the user had no control over the public IP and only accessed the Internet over NAT. Normally, when the other user needed to transfer a file to me, he/she started its copy of HFS and I downloaded form him/her; however, now the NAT thing didn't allow for that.)
Conclusion: it's a good piece of software. I recommend it.