Software is the "soul" of a computer, that is...
So, in essence, what constitutes a human is not the "hardware", rather the software. I am convinced of this, that if it were possible to slowly replace each neuron in our brain with a fully functioning but silicon based substitute that used standard electricity instead of the complex of chemicals required by our biological neurons to function, we could, quite literally, replace our "brains" with new hardware probably without noticing anything, except perhaps increased clarity of thought and significantly better memory. We'd also stop needing to eat and breath oxygen and be able to last much longer, presumably. The point is, each of us, our "ego", the I...would simply continue on because we are the software, not the hardware. You can replace an organ, an arm, an eye, a leg. We remain.
Ergo, if we are just software contained inside a relatively complex machine, we actually are "souls" in the sense that we are, to put it very primitively, software running on hardware just like a computer.
Continuing on that thread, we then, if it were technically possible, could be "downloaded" on to other hardware, say, smaller hardware that is miniaturized, or hardware that exists in a smaller paradigm such as using quarks, or if the string theorists are correct, as strings.
That tangent leads us to realize that since we know quarks and strings do not exist as we do, in a material plane, and can pop in and out of our universe, presumably if our conciousness could be contained by these things where they were functioning as neurons do currently on the macro [sic] scale, living with "brains" spread across strings would mean we could coexist in several planes, several dimensions. It would also mean we could simultaneously perceive across vast regions of space in several places at once, only as long as communication could occur between strings via hopping in and out of planes in a multi-dimensional space.
The short answer is, then, that the idea of God, souls, heaven, all of these universally held but as yet un observed and unproven phenomena become more possible. Given our limited perspective, however, it is still no more likely that that Christian explaination of all things is any more accurate than the flying spaghetti monster. A grand unification theory would explain a potential mechanism for this "spiritual software existence" to manifest itself across the universe, but until we managed to cross over by "upgrading our hardware" it would be impossible to know.
Another interesting point is speed/time. When you dream, you can experience days, weeks, or months in the space of a few minutes during what we clumsily refer to as "REM" sleep, 5-15 minutes of real (our physical perspective) time. To software though, time is not a constraint. A computer can process 1 Billion calculations in 1 second or less. Presumably our brains do something similar or much faster but in less easy to quantify ways as far as we can tell.
So, if we return to our "string" powered brains, we end up having the capability to live thousands of lifetimes in a nanosecond, and perhaps our physical 3d neighbours in universe 45Tg4b (ours), become rather like statues that take millenia just to move a finger. Impossible or at least completely uninteresting to even try to relate to. Have you ever tried to sit down and have a conversation with a mountain? Its simply moved 2-3 inches and you have lived and died 900 times. Talking to a physical person might be as boring as watching grass grow.
That said, of course, in our dreams, we escape to a world where we can experience the vastness of the universe in a blink of an eye, travel at the speed of thought , and defy our physical reality. Perhaps our less "land locked" neighbours do communicate with us in dream, their software interfaces with ours, and they show us sights. Who knows. If you assume our conciousness is effectively software locked in some relatively crude, large hardware (think a vaccuum tube computer the size of a warehouse compared to a digital PDA), there could be something to it.
Of course, this kind of olive branch makes one vulnerable again to the pitfalls of religion, that is, if all this is quite possible, who is to say that Joel Osteen is a quack? That L.Ron Hubbard wasnt making up his fanciful stories of aliens? That Joseph Smith actually did talk to Moroni and wasn't simply a moron. It becomes thorny for certain. Thus it is clear that we need to be vigilant in maintaining an intellectual clarity and openness to questioning everything, avoiding "sacred unquestionable knowledge" which I can still say I am an "a" to. "Asacrist" perhaps..."adogma", "asuperstitious"...it continues.