The only thing I see is that there might be some noise reduction being done. The photo of the guy at ISO 1600 looks like it's lacking detail that should be there, but I have to say it looks almost as good as some DSLRs with noise in high ISOs.
Here is a first look at photos from the Canon S90:
It looks like the Canon engineers proved their point that less megapixels can be better than more megapixels.
The portrait sample at ISO 1600 shows good detail and low noise.
The portrait sample at ISO 3200 has soft detail and medium noise.
It really shows up in the jacket the man is wearing.
But it is acceptable for a do-or-die shot.
This is much better than any other point and shoot class of camera.
For those people who want a small camera for concerts, this looks like a winner.
People who want more optical zoom, you might want to wait until you see samples from the new G11. It should produce similar results.