You'll note that there are differences between the gospel accounts. In my younger days, this troubled me a lot. I've had twenty years now to think on this, but while I won't claim to have fully figured it out (although I do have some thoughts I'll share in a moment), I have learned that the weight of the evidence is convincing, even if my belief in the Gospels' inerrancy remains troubled. Before I discuss some possible interpretations, it's fair to ask whether it's worth the effort. Lee Strobel in The Case for Christ rightly points out that there is enough agreement that the essential story is clear, and enough differences to indicate that the four accounts came from different sources. C.S. Lewis in Miracles (Chapter 16) points out that there's more to the Resurrection than the first morning:
When modern writers talk about the Resurrection they usually mean one particular moment--the discovery of the Empty Tomb and the appearance of Jesus a few yards away from it. The story of that moment is what Christian apologists now chiefly try to support and sceptics chiefly try to impugn. But this almost exclusive concentration on the first five minutes or so of the Resurrection would have astonished the earliest Christian teachers. In claiming to have seen the Resurrection they were not necessarily claiming to have seen that. Some of them had, some of them had not. It had no more importance than any of the other appearances of the risen Jesus--apart from the poetic and dramatic importance which the beginnings of things must always have. What they were claiming was that they had all, at one time or another, met Jesus during the six or seven weeks that had followed His death. Sometimes they seem to have been alone when they did so, but on one occasion twelve of them saw Him together [by twelve here C.S. Lewis (and Paul) means the Twelve, who in fact were only eleven by that point], and on another occasion about five hundred of them. St. Paul says that the majority of the five hundred were still alive when he wrote the First Letter to the Corinthians, i.e. about 55 A.D.
The "Resurrection" to which they bore witness was, in fact, not the action of rising from the dead but the state of being risen; a state, as they held, attested by intermittent meetings during a limited period (except for the special, and in some ways different, meeting vouchsafed to St. Paul).
The actual events of Resurrection Sunday are, for the most part, skimmed over very briefly in the first three gospels. Why? One reason is pointed out by C.S. Lewis--those events were actually a very minor part of the Resurrection story. The apostles themselves didn't see any of it, and the story told by the women didn't convince them. Women, after all, were not considered reliable witnesses in first century Judea, which may be another reason that their involvement wasn't dwelt upon. There are a few other points to keep in mind, which have more to do with the nature of ancient histories and biographies than the gospels themselves. The first is that chronology was never considered terribly important in ancient histories: the point is to tell the events, not necessarily to get them in an exact order. The second is that quotes are not full quotes. Go ahead and read the Sermon on the Mount (Matthew 5-7). I doubt it will take you more than fifteen minutes. Yet Jesus usually taught for hours on end. None of the sermons we have are full transcripts; they are all highly abridged, and that likely applies to all quotes found in ancient writings. Some commentators argue that all the quotes are paraphrased; they are at the least translations, as Greek, the language in which the gospels were written, was not the spoken language of Judea at this time. There are some scholars who believe that no quotation used by ancient writers is even meant to be exact, simply what the writers think the speaker should have said. I don't subscribe to that theory myself. The third and final point is that when listing people present, writers usually just listed the important people, leaving an assumed "and others." If you want more on the nature of ancient histories and the reliability of the gospels, I recommend F.F. Bruce's The New Testament Documents: Are They Reliable?
Since John is the most clearly different, and the most detailed of the accounts, we'll start with his gospel account and build on that. Clearly, John was telling the story of Mary Magdalene, so the focus is on her, and the other women aren't even mentioned. According to Luke, there were at least five of them there: he lists three, and then says there were other women (plural). Of these, four are named in the Gospels: Mary Magdalene, Mary the mother of James, Salome, and Joanna (I suppose it's possible that Salome and Joanna are two names for the same woman--I don't really know). The exact time is around dawn. John says that it was still dark, Mark says that it was "when the sun had risen." I'll admit that this bothered me at one point, but I don't remember why. It can be pretty dark just as the sun is rising, and I imagine the episode--travelling to the tomb, arriving, witnessing, then leaving--took long enough that it was dark when it began and light when it was over. In any case, Mary Magdalene arrives, sees the tomb is empty, then runs to get Peter and the other disciple (John, who carefully avoided naming himself throughout the gospel). There's no account of angels or Jesus yet in John. Of course, there's no mention of the other women either, and I wonder what they were doing. Did they go with Mary, or did they remain there? One possibility, which is one I've never heard mentioned in any commentary I've read, is that they split up. When they found the tomb empty, Mary went back to find Peter and John--perhaps alone, perhaps with some of the others--while the others remained there. There they saw the angels. This, then, could be the main source of the discrepancy between the gospels. If the other women remained while Mary went to get Peter, then perhaps there are two encounters with the angels, one by these women and one by Mary Magdalene, and perhaps, although I'm less certain of this, two encounters with Jesus. Jesus and the angels were, after all, in the area. Jesus would be meeting with lots of people that day, including some of his disciples on the road to Emmaus (Luke 24:12-32), and the apostles that evening (Luke 24:33-49). 1 Corinthians 15:5 tells us that he met with Peter before the apostles, although we're not told exactly when (he may have been one of the disciples on the road to Emmaus).
This resolves most of the difficulties involved, except for a couple of details. First off, how many angels were there? At least two. There could have been a whole choir involved in this event (I imagine there wasn't any lack of volunteers). All the accounts except Matthew's mention two, but Matthew's is the only one which has an angel doing more than talking to the women. After doing all the hard work of subduing the guards and moving the stone, before the women arrived it appears, this angel gets top billing in doing the actual speaking. Where were the angels? While Matthew's active angel was sitting on the stone at one point, there's no reason to assume he was still there when the women arrived. Who reported to the disciples? All of the women, apparently, but it seems that it was Mary's report, when there were still very few facts, that got Peter to go and look, as recorded in Luke and John.
This is clearly not the only possible explanation for the differences, and I make no claim that it is the correct explanation. It's simply the one that makes the most sense to me, but I've been convinced that the weight of evidence is such that the exact details are less important than I once thought.
Update: I made some grammatical and stylistic changes, nothing substantive.