So apparently Anonymous aka the troll factory have taken down Sony's ps3 online service for a bit. From what I am gathering, it is retaliation for Sony pursing legal action against geohot, who is known for his Ps3 hacks.
Anonymous decided not to attack the PSN since it wasn't hurting Sony - just the Sony customers. Even if there was a splinter group that was behind this... Without the full support of anon, they wouldn't be able to take down the PSN.
I think this is probably more related to the outage that Amazon had. Amazon datacenters went down for awhile and if Sony uses those datacenters and relies on cron jobs to prevent forgeries/hacking then it could possibly cause the PSN to go down for a few days while they fix it.