For conferences, "tracks" are used to organize presentations into similar groupings. For example, a series of presentations could be organized into a track called "Library Science". When an author submits a paper, they choose the most appropriate track for it to appear in.
One point that may cause confusion with OCS 2.0 is the distinction between Conferences and Scheduled Conferences. Since Conferences are often recurring events, we've written OCS 2.0 to support this explicitly. For example, you can create a Conference called "Public Knowledge Project Conference", and then create several Scheduled Conferences (e.g. 2007, 2008, and so on). Once you've created a Scheduled Conference, you'll have access to the typical management features e.g. Timeline.
We're working hard on the code for the initial release; you can expect documentation to follow shortly thereafter.
Public Knowledge Project Team
Don't miss the First International PKP Scholarly Publishing Conference
July 11 - 13, 2007, Vancouver, BC, Canada