Actually, according to recent excavations they were not using slave labor. The workers were well housed and fed, and came from all over Egypt for the work. They even left graffiti in the pyramids on their work. Kind of like "upriver stone-cutters rule!" (not exactly what they say, but that's the idea)There has been an official gov't policy that no slavery existed in ancient Egypt, but that's just nonsense. Of course there was housing for the slaves -- they worked on the project for generations, from the time of Sneferu, through Khufu, Khafre, Menkaure, and some lesser-knowns along the way. And even before the true pyramids, large mastabas surrounded (like the Giza pyramids) by large walls were being made, all by slaves.
Was the work voluntary? Well, in the vast majority of cases, no. Were they paid laborers? Yes. In fact, farmers used (and often depended upon) their government obligation to earn extra money in the off season. This is where the "involuntary servitude" label doesn't really fit either, which is why I said that it too is off the mark. Here's a few links. I don't have much time this morning, but will look a few more up late in the afternoon if you'd like.
One thing is for certain: the whipping and beating of slave laborers building the pyramid in the movie "The Ten Commandments" is totally wrong. It was what was thought at the time, but we know more about Egyptian society now.
Redding, who has worked at archaeological sites all over the Middle East, "was astounded by the amount of cattle bone he was finding," says Lehner. He could identify much of it as "young, under two years of age, and it tended to be male." Here was evidence of many peoplepresumably not slaves or common laborers, but skilled workersfeasting on prime beef, the best meat available.
The discovery of the town area reinforces the theory that ancient Egyptians utilized both permanent skilled labor, and a temporary workforce to complete the massive construction project.
While such temporary labor was not voluntary, Lehner suggests, neither was it slave labor in the sense most commonly assumed.
(more on government obligation)
The pyramids were probably not built by slaves because slave labour was not widely used in Egypt at the time. Peasant farmers, however, were required to spend a number of weeks working on construction projects. This provided the paid labour needed to build these gigantic structures. Since the fields were under water during the summer, wages earned in building the gigantic pyramids supplemented the family's income.
P.S. I tried my best to avoid quoting Zawi Hawass, but I was in a bit of a hurry. If I did so accidentally, I apologize. I really can't stand him. :-)