What router do you use sorry? go back into routers settings, Find your IP of the PS3 by looking in DHCP and note it down... and then there should be a setting called "Virtual Servers" or "Port Forewarding" all you will basically have to do is, (on my router) Belkin Wireless 54G F5DXXXXX ? I go to virtual servers and see this page.
Then enter the Port foreword numbers in the above post. and the IP of your PS3.... And click save.... you will have to do this for each number.
I.E TCP:80, 443, 5223 this will take 3 virtual servers.... I probs havent explained that very well. But I will try and find an link to some forum explaining more lol.