Check with you ISP to see which ports they block. You can usually do this via their website's FAQ. Should they block the relevant ports.... 21 for FTP, 80 for HTTP etc.... it's just a matter of setting up port forwarding via your router's configuration page.
Assuming you have a dynamic IP address you will want a host to point toward your ever changing IP... I recommend no-ip.com. Then you can simply type in
shane@whatever.something.com and end up in your FTP directory. Please note... the speeds will be slowish.
I'm sorry if I am scant on details... but it has been years since I have done any of that. I am hopeful someone else will come along who can fill in these gaps.... I'll check back here on this thread, and I'll dig around and research it for ya if no one else knows it off hand.