EDIT OK it has come to my attention that this may not work on well, alot of routers, however it does work on linksys and netgear routers it is probably worth a try even if you dont have one of those
Here is how i got my dedicated server on the internet, it only took me about 5 minutes and the other tutorial on this looks like it takes hours :(
First off, i typed in my local IP into my mozilla, no www. or .com, just my IP
Next put it in your username and password.
Go to advanced---->forwarding
Make a new entry called SRCDS
Ports 27015 through 27016 (assuming you run your dedicated through those ports) and check all the Protocol TCP & UDP boxes. And of course the enable one.
Press apply and then quit that browser. Open up your dedicated server and in the console type "sv_lan 0" or you can simply put that in the autoexec.
Go to this website
Take your IP and put a :27015 on it, so as an example you would do
the other pic is of my dedicated :)