atomicgamer.com has a great story about ps3 hacks and specifically the technology behind it. it’s kind of an older story, but it highlights exactly the reasons why sony is kind of in shit over this whole hacking business. this is a summary, but please read the full story for the juicy details.
It’s possible, even probable, that Sony won’t be able to keep hackers and cheaters off of PSN. The 360 can by way of a permanent ban of a specific console and is only possible due to unique console IDs hard-wired in, but rumor has it that these can be changed on the PS3. Depending on how Sony set up that security, it might be impossible to stop people from logging on with a new ID every time.