There is ice on Mars.
Photos of the spots where the Phoenix Mars explorer dug a few days ago show that some of the white material that was exposed has disappeared. That almost certainly proves it’s ice, water in solid form, that has sublimated (that is, gone directly from a solid into a gas, rather than melting from a solid into a liquid). If the white stuff they’d uncovered had been salt, it wouldn’t have sublimated.
As I wrote yesterday, Phoenix has been digging in a new spot. That effort stopped when they hit a hard layer: more ice?
They also seem to have figured out (though they haven’t explained) what was causing those memory overruns yesterday. They’re uploading a software patch to address it. In the meantime, they’re downloading the new scientific data each day and not trying to store it in case it gets bumped out.