Hi, Beak.
My kids (8 & 10) has been asking questions about heaven/hell/souls/reincarnation since they were small (about 3). We are a family full of contrasting opinions on religion (atheist, agnostic, Christian, Buddhist, Wiccan) so I think they were just recognizing and responding to the fabric/undercurrent of their family.
Our goal has always been to provide a framework as well -- and allow them to make their own decisions regarding belief/spirituality as they grow and learn. I ALWAYS turn questions around to my kids when they ask ANYTHING. So...I have used that technique with religion questions as well.
What's heaven? from my son turns into "What do YOU think heaven is?" from me. (followed sometimes by a long conversation, and sometimes by a brief response from him and then on to something else). I will happily tell them I don't have all the answers and can and will share what I believe/don't believe with them, but I also encourage them to make their own decisions and have since they started asking.
Incidentally, my daughter considers herself an atheist, and my son falls solidly into the Christian range. (No one in our IMMEDIATE family is Christian, btw, just grandparents we don't see much).
I think, as long as it fits into your family's framework as it has ours, that allowing them to wonder and come to their own conclusions is a positive decision.
Have fun!
Sarah
