Hello,
Assuming your content is legal, you can set up a Linux, a Mac, or a Windows computer to be an FTP or Web server. Mac OS X has it built in, Linux you can install it easily, and if you have Windows Professional, I am sure you can find some freeware or shareware to get the desired functionality.
All the people looking for your stuff will need is an IP number, and to know if they should use FTP or Web applications.
But YOU will need to ensure that the server is secure. Do you want everyone to get to it? Do you need username/passwords? Did you make sure no one can write to your server, so that some schmuck on the internet doesn't fill your server up with child porn, and then calls the cops on you? Having a computer on the internet is a responsibility, ya know.
I do not know what you intend to share, but assuming you are on a cable / dsl link, it is going to take people a while to move something like a CD-ROM through the wire. Off the top of my head, I think I did that one time and it took around 6 hours to move the CD-ROM. ISP's throttle back the "upload" side of things, unless you purchase their business plan package.
Christian