When do we actually go to Heaven?

If you have ever been to a funeral then you I'm sure you have heard a preacher say that so and so died and now they are in Heaven with Jesus. 

But are they?  Let me be clear that I am not questioning whether they will eventually be with Jesus.  I have no doubt that they will be.  I am just questioning the timing.  Here is an example of what triggered the question.

 Acts 24:14-15(NKJV)

But this I confess to you, that according to the Way which they call a sect, so I worship the God of my fathers, believing all things which are written in the Law and in the Prophets. 

I have hope in God, which they themselves also accept, that there will be a resurrection of the dead, both of the just and the unjust. 

Isn't it at the resurrection of the dead that we will all be judged?  Isn't that when we stand before God and Jesus and they look to see if our names appear in the Book of Life?  If that is the case, doesn't that mean that nobody is in Heaven yet? 

I'm going to have to look in to this so I have a better understanding of it.