I found connecting to be easiest by assigning an IP address to the PS3 in the router's DHCP settings and enter the numbers manually in the PS3's settings.
Go into System Information in the PS3's Settings menu and write down the MAC Address, you will need this while adjusting the router. Now go into the router set up and make your way to the DHCP settings- it should be the last blue button on the left side of the screen. First make sure DHCP Server is Enabled at the top. Further down you see Static DHCP- this is where you need to be. Select Enabled and put in an IP address finish that you know won't conflict with anything else- 125, perhaps. next enter in the PS3's MAC Address in the blanks below and hit Apply.
With that done go to the Status tab and leave this up- you will need the numbers here for Subnet mask and DNS Servers. Now go back to the PS3 and edit in the numbers, including the IP address you set up on the router. If you are using encryption on your router you will need the key to give the PS3 so that it can be IDed as a friendly to the router. Once you have the settings in you can go all the way to the end to save settings and test things out. You should now have no problems getting online.