Any ISO above 800 in P&S cameras is useless. There's two
types of noise, chroma and luminescent noise. In the current batch
of P&S cameras, all of them have a lot of both.
As long as the P&S camera is able to reach ISO800, it should be
enough for most. For DSLRs, it's a different case.
The ability for a camera to shoot high ISOs depend little on the
camera's hardware capabilities, since it is just an amplifier
controlling the sensor gain. Rather than looking at how high an ISO
the camera can go, look more at the amount of controls a P&S
camera can give you, its ease of use as well as image
quality.
You can check out comprehensive reviews at this site: DPReview, though
their reviews are geared towards the higher-end user.
