Bishop N. T. Wright gives a brief answer:
And what does heaven look like?
So what does the crucified Jesus mean when he says to the thief on the cross, "Today you will be with me in paradise" (Luke 23:43)?
But what if all of this doesn't sound like what I was taught in Sunday School?
For more, read Wright's book Surprised By Hope: Rethinking Heaven, the Resurrection, and the Mission of the Church (HarperOne, 2008).