damn, nice find. it was like 15 years ago that i read that (in a physical book), and i was trying to find it on the Zinn site and looking all the way back at the 17th century chapter on early slavery, which has similar stories but wasn't the one i was looking for (the one you found). but anyway, here's another cool bit:

Chapter 2: Drawing the Color Line

From time to time, whites were involved in the slave resistance. As early as 1663, indentured white servants and black slaves in Gloucester County, Virginia, formed a conspiracy to rebel and gain their freedom. The plot was betrayed, and ended with executions. Mullin reports that the newspaper notices of runaways in Virginia often warned "ill-disposed" whites about harboring fugitives. Sometimes slaves and free men ran off together, or cooperated in crimes together. Sometimes, black male slaves ran off and joined white women. From time to time, white ship captains and watermen dealt with runaways, perhaps making the slave a part of the crew.

In New York in 1741, there were ten thousand whites in the city and two thousand black slaves. It had been a hard winter and the poor—slave and free—had suffered greatly. When mysterious fires broke out, blacks and whites were accused of conspiring together. Mass hysteria developed against the accused. After a trial full of lurid accusations by informers, and forced confessions, two white men and two white women were executed, eighteen slaves were hanged, and thirteen slaves were burned alive.

Only one fear was greater than the fear of black rebellion in the new American colonies. That was the fear that discontented whites would join black slaves to overthrow the existing order. In the early years of slavery, especially, before racism as a way of thinking was firmly ingrained, while white indentured servants were often treated as badly as black slaves, there was a possibility of cooperation. As Edmund Morgan sees it:

There are hints that the two despised groups initially saw each other as sharing the same predicament. It was common, for example, for servants and slaves to run away together, steal hogs together, get drunk together. It was not uncommon for them to make love together. In Bacon's Rebellion, one of the last groups to surrender was a mixed band of eighty negroes and twenty English servants.

As Morgan says, masters, "initially at least, perceived slaves in much the same way they had always perceived servants... shiftless, irresponsible, unfaithful, ungrateful, dishonest..." And "if freemen with disappointed hopes should make common cause with slaves of desperate hope, the results might be worse than anything Bacon had done."