What is heaven? N.T. Wright has the answer.
Here is an important recent interview with N.T. Wright about correct Christian understanding of heaven. While teaching of Wright are often rather controvescial, here he presents an orthodox teaching that is oh so often missed nowadays.
So what is life after death? Here are the main points:
1) There is no heaven (or hell) right after death. Instead, we enter so-called itermediate state. It is not clear what happens during this state. We will be with God and with Christ, resting and being refreshed, we will be conscious, but compared with being bodily alive, it will be like being asleep.
2) What is more important is the next stage, life after life after death - the final place where we will live forether, which can only be entered after the final judgment. But this place is not some place in the clouds but rather a renewed physical Earth where our current bodies will be resurrected into something completely different.