Some dude, geohot, has put in a LOT of work to get hypervisor level access to the PS3 hardware.

He’s been working on it for quite some time – Sony have put together a very good and well protected system. They document almost everything about the PS3, keeping it quite open, but still it’s protection has stood the test of time for more than three years, and I’m sure that’s not through any lack of people trying to break it.

From what I can understand, he is using the OtherOS (so, this will not work on the new Slim PS3) and has some code that allocates a chunk of memory. He then deallocates it, but during the deallocation, he glitches the memory bus so that the hypervisor thinks that the memory is deallocated, but he still has a pointer to. He then reallocates the memory and maps it to somewhere interesting, and because he owns the pointer to that slab of RAM, he can read and write it as he sees fit. Or something like that anyway…

On the PlayStation 3: Here’s your silver platter.

Here’s another writeup from EuroGamer.