When you think about what Void is, it makes a certain sense that there's Nothing much to read about it.
Seriously though, Void is nothingness. The primary thing that I've found it useful for is drawing things in. Pulling, crushing, consuming, unmaking... these are traits of the void.
Consider the number Zero, and the strange traits that it possesses in Mathematics. Any number, if multiplied by Zero, equals Zero. Any number, if divided by Zero... well, High School Mathematics will tell you that it's undefined, and you can't do that. The short version of the higher math answer is that dividing by Zero equals Infinity -- and that Zero and Infinity are Reciprocals. In other words, Zero * Infinity = 1.
There is at least one scientific theory that proposes that empty space is actually equilibrium between what we'd call energies. So perfect, unmoving balance is, in a sense, destruction, while it is through imbalance that matter, action, and life come about. Assuming this can be applied to Void magic, a subject with which I have no experience and little knowledge, you could utilize the Void as a force of creation and control over the balance of energy. Just as shadow is defined by the presence of light, void may also be defined by the presence of...well, anything. Just my two cents.
That's an interesting point, and I may need to experiment with that myself.
It does also bear mention that every psychic vampire I've met and talked to has a sort of void or vortex in their chests that draws energy into itself. That may be what you're sensing in yourself, Nergal.
In any event, feel free to send me mail if you'd like to talk further, I'm afraid I'm not very good at remembering to check back in on threads here.
I looked up the element Void from Japanese mythology, it turns out to be a different word for spirit energy, creativity, or the Aether. The word itself, I think, is meant to refer to the sky or Heaven. Zen Buddism also recognizes the Void, though uses it in the context of emptying your mind. I'm not sure if this is relevant, but I wanted to make sure.