Yo ppl ! I have another way which is better n faster than hippo's ! In my way, I usually do it when I turn my ps3 on n off .So the first thing you have to do is go to Setting in your PS3, go down to the Network Setting, choose the Internet Connection and Disable it . After that, turn it on again, and sign in the PSN then get into the game . To the Multiplayer mode, find game n it will show u the board right away, for those cases which show the Downloading Game Setting board, just wait for a second, it will sort itself out . I recommend u guy should turn the internet in ur ps3 first n turn off the system then turn it on again, after that u do like the things I tell above .
simply is : Turn off --> on the internet, sign in the PSN, get into game n Find Game. ( if it not working, try it again, will probably works )
This method always works for me (100%) . So try this n reply to me if it works or any questions . Goodluck ppl