The nightime versions are officially 2 hours (though we'll stay as late as folks want) and the morning version is 3 hours.
As for content, we're going to have akeynote presentation on some of the philosophies that we see in the most effective PTOs and PTAs. And we'll have a "40 ideas in 40 minutes", high-energy idea-session (key topics like appreciation and better meetings and welcoming new volunteers, etc.). The extra morning session will be a fundraising session.
The price is very low and the rooms aren't all that big (about 100 attendees per JamSession) -- so we expect high demand and quick sell-outs. All of our spring 2005 full-conferences did sell out, so we suggest booking fast if you'd like to attend.