You can transfer files to and from a friend's computer over the internet. One side needs the client version and the other (the one with the files or where the files are going) needs the server version. Or if it is easier, have both the server and the client on both machines. Your choice. It works on Windows, Linux, and Mac.

When you go to download Filezilla, notice that you're downloading the Client, BUT there is a download link on the left under the Server Heading to download the server version. Enjoy