first you need to open choosen port in your router.
make sure you open it to correct computer.
(
www.portforward.com)
then find out your ip.
(
http://www.ip-adress.com/)
lets say you choosen port 8080.
then tell your frend to goto :
http://your ip here:8080 (
http://123.123.123.123:8080)
if you have a dynamic ip it wil change every time you connect to internet , then you need a no-ip/dyndns account.
or else you have to find out your new ip every time and send that to your frend.
if you choose a no-ip adress you can have HFS.exe keep track of your ip and update that for you.
then your frend can just use your no-ip adress like this :
http://mycooladress.no-ip.comif you have a static ip that never change you can reg a real web adress and point that to your ip.
ofcource you can still use a free no-ip account/adress
but the most inportant thing is to get your choosen port open in your router or else it will never work.