A mind is information. The fine structure of the brain is a mind, information stored in physical structures we are slowly beginning to understand. Preserve the structure of the brain after death, and there is the possibility of restoration to life at a later date, through the use of plausible future technologies. The important thing is that the information is retained - with that in hand, all the details of future restoration from death are well within the realm of what physics tells us is possible.
All we can do today is the preservation part of the equation - but that's all we have to do for now. The dead have all the time in the world to wait, provided we can maintain the fine structure of their brains. Cryonics providers vitrify the brain and body for low-temperature storage in vats of liquid nitrogen, indefinite storage after death paid for by life insurance in most cases.
But why cryonics? Over at Depressed Metabolism, Greg Jordan makes the case for the development of low temperature storage infrastructures to be something of an accident of history. Other options exist:
Twenty years ago, Charles B. Olson published an article called "A Possible Cure for Death" in the journal Medical Hypotheses. In it, he favorably compares methods of chemical preservation to cryogenic preservation. Unfortunately, this article provoked no wide discussion or attempts at implementation. As the author notes on his website, other than requests for reprints, "nothing more came of it." And yet the arguments in it are still sound and just as persuasive today as they were then.
Part of the confusion around chemopreservation concerns the quality of preservation that is possible with this method. Chemical methods of preservation such as fixation are not only adequate, they have long been the gold standard for biologists studying the structure of cells and the brain.
If personal identity is preserved in the brain in physical structures such as synaptic circuits, then we know that chemopreservation can preserve these structures just as well as cryopreservation.
It makes for interesting reading material, though I'm not sure that the economic argument in favor of chemopreservation can be made without a better analysis of the infrastructure you'd need for continuing safe storage of the preserved. See what you think.