Think about what the conditions are. The temperature is very low (meaning that things would freeze); the pressure is very low (meaning that volatile things like water will evaporate). It sounds a lot like freeze-drying.

The effects on a living human are called the bends, or decompression sickness, and are caused by dissolved gas bubbling out of the blood, especially at joints. Severe cases can cause destruction of tissue and eventual death, with swelling and even seepage of blood or lymph through the skin. It's not likely to be quite like you see in some of the gorier space epics, with exploding eyeballs and such; but the bends are just as deadly if less spectacular. The FAA has posted an online pamphlet on high-altitude decompression sickness (old link). A human body would not disintegrate, at least not in the sense of coming apart.

A dead body in space is likely to be rapidly mummified as water is evaporated; the effect would be similar to that of burying a body in dry, alkaline soil, as in Egypt (this is thought to be how the Egyptians learned to embalm) or to, for example, the Iceman, who was freeze-dried.

Incidentally, bacteria are likely to be killed just as dead by the freeze-drying process, so bodies would not decay in space.

Incidentally, there are a lot of data on decompression sickness from Nazi Germany; concentration camp doctors performed decompression experiments on prisoners, usually "testing to destruction." There's an ongoing debate in medicine about whether to use these data, since they were obtained by immoral means.