Sounds good. Have you seen Epic Win or Chore Hero? Both are iPhone apps that seem to do most of what you say here (haven't used them myself).
I've seen a few of these sorts of sites around, but they seemed to lack incentive or real motivation. How many people have tried a bunch of To Do apps and never stuck with any of them? I just keep going back to scraps of paper.
Of course, to-do apps and choretrackers are like black holes for developers but I can't help but wonder if there's a tack yet to be tried with both.