Let me preface this by saying that I have always explained God as the "creator"... Here is a conversation I had today with my 5yo.
DS: Do all Americans believe in Allah?
EW: Well, I think most Americans believe in one God... But they don't call him Allah.
DS: On the day of judgment will they have to meet Allah too?
EW: Yes, all the people who ever lived on earth will be before Allah on the day of judgement to talk about the good things and the bad things they did while they were alive.
DS: But how will they talk if they are dead?
EW: Well, since Allah created us he knows how we work and he can make us again.
DS, after much thought: So, like I know what is in cookies... Powder (aka flour) and butter and sugar... So I can make them whenever I want. So Allah has all the 'gredients (aka ingredients) to make us come alive again! Like that?
EW: Sure, kinda like that;)