How many resurrections (raptures) will there be? Revelations 20:4-6 NIV
  4 I saw thrones on which were seated those who had been given authority to judge. And I saw the souls of those who had been beheaded because of their testimony about Jesus and because of the word of God. They had not worshiped the beast or its image and had not received its mark on their foreheads or their hands. They came to life and reigned with Christ a thousand years. 5 (The rest of the dead did not come to life until the thousand years were ended.) This is the first resurrection. 6 Blessed and holy are those who share in the first resurrection. The second death has no power over them, but they will be priests of God and of Christ and will reign with him for a thousand years.


It sounds like this is referring to the rapture.  However, it sounds like there will be more than one of these resurrections.

How many will there be?
Looking at the passage you quoted, it seems pretty clear that there are two resurrections.  The first resurrection is the resurrection of the righteous, while "the rest of the dead (the wicked) did not come to life until the thousand years were ended."

It doesn't look to me like it's saying anything about the Rapture; merely that those who were righteous in life will be resurrected quickly and be able to "be priests of God and of Christ and... reign with him for a thousand years," while the wicked remain dead until the second resurrection, at the end of the Millennium.