https://secure.isandt.com/wwwftp/ftp.cgi
That is a web based FTP client.
Give your friends a link to that, and give them your FTP username and password.
If you need to set up an FTP Server, you can use
FileZilla Server. Make sure you get the server and not the client. It will be a bit complicated, but we can go through it step by step.
(note, if you don't like FileZilla, browse sourceforge. I'm sure there are hundreds, if not thousands, of FTP servers there.