If you do not mind having other people see your camera's images, then what you yourself suggested, port forwarding for port 80, is perfectly Ok.
Why do you say that it did not work? Is it because you tried to access your camera, from within the same LAN, but by trying to load your public IP address into your browser?
If this is so, then relax. Many routers (not all) will prevent that, i.e., they block LAN-side requests to their own public IP. Strictly speaking, it might even be your own ISP blocking that, not just you. If this is the first time you try this, then the only way to know for sure you incorrectly configured port-forwarding would be to try from some external location, like your school/office/internet cafè, whatever. If you still cannot get an image, then you are right, there is something else, but until then, you cannot be sure.
If it is something else, a list of things to check:
1) you have a modem, and you did not port forward on the modem (there might be no need to do this, but it is surely a point to check);
2) you have a firewall on, perhaps on your modem, and/or your router.
3) Your modem or router has something like Disallow WAN-side port 80 connections. This is generally done to prevent people from trying to re-configure your router from outside your LAN, which would compromise your net completely.
4) your pc has a firewall on, which allows LAN-side connections, but forbids WAN-side connections.