I hate to sound repetitive here, but this just isn't so, and the specs that lay this out have been public for a long time.
The Cell (PS3 CPU) and Xenon (Xbox 360 CPU) are very, very similar in terms of capabilities. This shouldn't surprise anyone. Their CPUs are made by the same company (IBM), on the same process (IBM Microelctronics' 90nm), and all three of the Xenon's cores are almost identical to the main core in the Cell (Xenon has more cache and a few extra features; Cell has 7 sub-cores that are less powerful/more specialized).
They both have the same amount of memory (the 360 has 512 MB of unified RAM; the PS3 has 256 MB of main memory and 256 MB of video memory). They both have 2005-esque GPUs from leading PC video card makers (the Xenos GPU for the Xbox 360 is actually a more forward-looking design than the RSX, which is pretty much a GeForce 7800).
They both have a hard drive (the PS3's is larger, but this isn't really important for a game). They've got pretty much the same style of controller.
The only thing the PS3 really has to differentiate itself from the 360 is the Blu-Ray drive, and that's just not a big deal for games; if something's actually long enough that it doesn't fit on a DVD, spanning multiple DVDs works just fine.
Leading game developers say if you really, really work at it, the PS3 has a slight edge in CPU, the 360 has a slight edge in GPU (and most modern games are GPU-limitted), and the 360 is easier to code for. But at the end of the day, one system won't have better-looking games than the other (at least, once developers really figure the PS3 out; for the next year or so, you'll have 2nd-gen 360 games against 1st-gen PS3 games, and the 360 games are going to look better).