Try checking out: http://portforward.com/
They have guides for a ton of different routers, though I will caution you. If you don't know much about networking and how the internet works port forwarding can be dangerous. Honestly I'm not precicely sure why but I'd bet it opens you up to easier attacks from viruses and hackers.
Here's some information, or opinions, on that the dangers of port forwarding:
http://forums.bukkit.org/threads/what-are-the-dangers-of-port-forwarding.58297/
Enjoy,
Thewait