Apple released updates for all three iWork apps yesterday. The updates are available through Apple’s software update or as direct downloads. Apple was typically circumspect in their description of the updates.
This update addresses compatibility with Mac OS X.
Keynote 4.0.2 gets the relatively long description of:
This update primarily addresses performance issues while playing or exporting presentations.
I rarely use any iWork app but I didn’t have any problem installing the updates or opening a document in each app after the update. No reboot was required.