You get reincarnated after soul society. Kenpachi said so in one the chapters:
Originally Posted by zaraki kenpachi
And if we die, we'll just change a little, and then we can fight again!
By change a little, he means:
1. Name change. (Let's say, in souls society, a guy named Rupert died and was reborn in England. I don't think they'll call him Rupert again, do you?)
2. Maybe appearance (When you die in soul society, you could have a mullet. But, once you've died again and came back to soul society, you could have gotten a mohecan(sp?).)