Leopard's iCal replaces the event editor palette and drawer with a pop-up window that points to the event being edited. The problem with this is that it occludes other events that you may need to see. If you need to see these entries, simply click on an area in the pop-up that doesn't contain a widget, and drag the window out of the way.
This feature wasn't immediately obvious me because I assumed that the pop-up was "pinned" to the event. Not so.
[robg adds: See the new poll to express your opinion on the new vs. old iCal interface.]

