This link has a nice table outlining the differences and similarities.
PS3 Xbox 360 comparisonQUOTE
We're not saying to ignore specifications altogether--most of them are relevant in some way or another. And we're going to talk about the specifications that really jumped out at us at first glance. Let's start with the processor. Sony has announced that the PlayStation 3 will have a 3.2GHz Cell processor that consists of a PowerPC-based core with seven synergistic processing units. The PS3 spec-sheet says that there's an eighth SPE reserved for redundancy--whatever that means. The Xbox 360, in comparison, has a multicore PowerPC processor that has three dual-threaded cores that can handle six total threads at a time. You might be able to call the Cell's SPEs overgrown math units, but we think Sony's Cell processor wins from a brute power perspective.
The PS3 will be the better performer I think, but does that realy matter? What matters most is what games will be available, and which most consumers will buy. With MS selling the Xbox 360 at a loss will certainly make it cheaper than the PS3 I think.
But I dont realy care. My last console was a NES immatation. I when I say it was my last console I mean it....
I only care for the console wars in that it will help determine a winner between HD-DVD and Blue-Ray.
Sony is more concerned with keeping a tight grip on its acorns than it is with giving the consumer what it pays for.
I just wish for the evile empire that is MS to shove its foot up the more evil empire that is Sony's ass!