First you must have the minecraft server application program and set it up. If you don't know how to do that, go here: http://www.minecraftwiki.net/wiki/Setting_up_a_server. Afterwards you have to port forward your ip address. To do that you have to change the settings of your router. You have to find a setting about reserved dhcp address and click add. Give an ip thats the same first three numbers, but the last is between 1 and 254. Afterwards you have to change another setting about port settings. For all the ip it asks you just put in the reserved dhcp adress you made earlier and for the port say 25565. Afterwards find your ip address here: http://mywanip.com and add :25565 at the end of the ip. e.g. 188.8.131.52:25565. Hope this helps.
BTW i dont have a belkin router so i dont know if the setting are different. If it doesn't work just PM me