With all this success with Limbo on XBL is it a possibility to see this game on PSN?

I would imagine there is, but, alas, not from us. I'm fairly certain we don't own the rights to Heart of Darkness. While we published it, we didn't develop it. You might check with Eric Chahi:

http://www.anotherworld.fr/anotherworld_uk/

Great game! I'd love to see it available again.