Hello well if you are working on a lan server from your computer then you will not be able there is two way I know you can make a server
one you download hamachi and make it from there while downloading the server minecraft from minecraft website
second you can try to make a bukkit server almost exactly if you look it up will show you how to make one
by making this two of servers you can now get anyone to come if you want to spread the word for people to join make a forum for it on minecraftforums or go on youtube or facebook to make people join.