Following today's, Apple has issued updates to iPhoto and Aperture, which bring the latest versions of the popular photo management suites to 9.4 and 3.4, respectively. The updates include a number of small bugs and fixes, along with new features and addresses several notable issues.
The first of these is both programs now support Shared Photo Streams in OS X Mountain Lion, which allows others to view Photo Streams you have set up in iCloud. In addition, the programs now support directly opening and editing a file from iPhoto in Apple's Aperture program and vice versa, if you have both installed.
More minor but significant features specific to iPhoto are the ability to add comments to photos that have been published to Facebook, and new card and calendar themes.
These updates requires OS X 10.8.2 to be installed, so if you have recently run Software Update and applied the latest OS update, be sure to check again and download the updates if you regularly use iPhoto or Aperture. The updates are around 757MB in size for iPhoto and 555MB for Aperture, and should not require a restart of your computer to install.
As always, be sure to fully back up your computer before applying this or any other update.