hi, bluecoder, i got your message in my past topic which handles exactly this.
Basically what the others have told you so far is 100% right and as fara s I'm aware you have probably just missed something which has thrown you off course.
Your computer is on a nework, to identify itself on the network it has an internal IP 192.68. bla bla, your modem has a seperate IP to identify tiself on the ISP network.
First step to take is make sure that others know the external IP.
Secondly you need to have apache, php and myself running for any sort of thing to happen.
thirdly if you are behind a router it needs to be configured to send HTTP requests on Port 80 to the computer with apache etc running. ie: the computer with ip address 192.68 bla bla (where that si your computer with the files etc).
Now, in theory this all should work no problems. But you most likely will have a problem. I sure as hell did.
If it doesnt work, you are connected to the internet and apache and php etc are running fine try logging into the routers configurations and take a look at whats happening there.
[url]http://192.128..1[/url] is often the url for the router.
Now, each router is different but for mine i go to the Virtual server setting. A virtual server is basically a rule which the router deals with. If a request for something on port 80 comes to the router it forwards that request to a certain computer within it's network which should respond accordingly.
In my router it was simply a case of typing in the internal IP (192. bla bla) and specifying which port it was to act on and whether it was TCP or UDP.
And thatw as it, my fileserver worked!
However, if you are still having problems make sure that apache is listening on port 80, you'll find that in the configuration file for apache.
Hope it works out for you!