What Happens - 1 Thessalonians 4

And then this: We can tell you with complete confidence—we have the Master's word on it—that when the Master comes again to get us, those of us who are still alive will not get a jump on the dead and leave them behind. In actual fact, they'll be ahead of us. The Master himself will give the command. Archangel thunder! God's trumpet blast! He'll come down from heaven and the dead in Christ will rise—they'll go first. Then the rest of us who are still alive at the time will be caught up with them into the clouds to meet the Master. Oh, we'll be walking on air! And then there will be one huge family reunion with the Master. So reassure one another with these words. 1 Thessalonians 4:15-18

SO have you always thought that when a follower of Christ dies…he/she goes immediately to heaven. Well….you can keep on believing that.
Scripture shows that to be the case in several examples;

• the beggar died, and was carried by the angels into Abraham's bosom: the rich man also died, and was buried; And in hell. Luke 16
• "And so it is appointed unto men once to die, but after this the judgement:" Hebrews 9:27
• We are confident, I say, and would prefer to be away from the body and at home with the Lord. 2 Corinthians 5:8
• For to me, to live is Christ and to die is gain. Philippians 1:21

What this passage is talking about the “Rapture” and the Christ calling up the BODIES of the dead. There is obviously a difference between the body of the dead and the soul of the dead. I believe that once we die….our souls are in the presence of Jesus, where we will worship him for eternity. Our bodies on the other hand, bound by death and decay will lay waiting for the time that Jesus calls for them prior to His return, where our bodies will take on a new form, free from corruption (1 Cor 15:51-53).
For more on this:
http://en.wikipedia.org/wiki/Rapture