Matt Hamilton has blogged about his Code Camp Oz 2008 experience. I to think that it was a really great event this year and the Twitter feed really added another dimension to it. I actually integrated Twitter into my presentation taking a brief from my customer via Twitter.
Next year I think that it might actually be worth integrating Twitter feedback into the event in a more visible way (if it is still the new hotness :P) by connecting a secondary projector up and pumping the hashtags feed directly onto the wall.
Not sure what people think about that.