What is the difference between the Kingdom of God and the Kingdom of Heaven?

I did a search and saw that the phrase "Kingdom of Heaven" appears exclusively in the Gospel according to Matthew. However, the phrase "Kingdom of God" appears a few times in Matthew, but is also quite prevalent in Mark and Luke. It also appears twice in John 3, several times in Acts and Paul's letters. Clarence Larkin has a diagram that seems to distinguish between the two kingdoms somehow as well: What, then, is the difference or distinction between these two kingdoms?