File sharing over the internet

Hello,

I believe this questions has crossed the internet many times but i can't seem to find the right awnser.

So here it is as the title says:

How to share file's over the internet with another mac.

I know how to setup a home network and i really like the idea of AFP.

"afp://10.0.1.4/~joey"

So my actual questions is:
How can i make my "friends" connect to my computer to share clips with them. Without them having to download from my computer. more like streaming...

i hope this gives you guys enough information.

Thanks in advance,

Joey

ps.
Maybe a way to share clips of "Air video server" from mac to mac?