^ Motorola SBG 6580.
SSID is free and open.
Other devices connect to Guest network fine.
This router only outputs 1 frequency at a time -- 2.4 gig OR 5 gig.
I don't see an Authentication setting.
Made about 12 port triggering entries as per on-line guides.
So you've set the wireless to 802.11G @ 2.4 GHz, right?
Port triggers are only for NAT purposes, it won't solve this connection issue or prevent it joining the network.
For testing purposes, can you allow it to connect to your LAN? The guest network shouldn't prevent the PS3 joining, but it's just something to rule out.
According to the manual, MAC filtering is found here:
On the Wireless Access Control Page, be sure the MAC address for each affected wireless client is correctly listed.