If u don't a broadbandrouter it's ok to forwarding. Every1e uses xp is strongly recomended to turn on "UPnP" in the routers configuration site, accessed on internet.
You could type "http://xxx.xxx.x.x" Whereas "x"'s is the routers ip address
Linksys uses "192.168.1.1" D-Link "192.168.1.100" SMC "192.168.2.1"
Linksys psw is "admin" same for the d-link I think. SMC uses "smcadmin"
If you let me know which bits are too tricky, or which bits aren't clear, I'll try and tidy it up as soon as I can
Port forwarding is a very tricky business, and depends very much on your setup and equipment you use. The base line to remember is, if you directly connect to the internet you won't need to port forward. But you may need to open the ports in your firewall.