IIW is not a traditional conference; it's an "unconference" working session, and everybody participates, so if you're coming, you'll want to bring your ideas and your laptop. There will be a hands-on intro session which covers the use of various Web 2.0 identity technologies on Monday morning, and the main "open-space" sessions begin at 1pm on Monday.
Tuesday afternoon there's a slot in the schedule for demos, so come prepared if you've got something cool to show to the community.
What I'm really looking forward to this time is the business models discussion. I'm researching business models for identity services this quarter, so I'm really looking forward to bringing something to the discussion in Mountain View, and I hope others come ready to talk about what works & what doesn't work too.
If you're planning to attend (I am), the organizers are offering an early registration discount. The attendance fee is quite low to begin with, but in today's economy every dollar helps.