It weighs in at a whooping 667.7mb update.
You will need to update Lion to 10.7.2 to take advantage of the iCloud feature.
Aperture 3.2 supports compatibility with iCloud and iOS 5. This update also addresses minor stability, performance and compatibility issues, including:
Resolves an issue that could cause the “Loading” indicator to reappear in the Viewer when cropping a photo
Aperture now automatically relaunches into Full Screen mode if the application was in Full Screen mode when last quit
Pinch-to-zoom gesture now automatically activates Zoom mode in the Viewer
Left and right swipe gestures can now be used to navigate between photos in the Viewer
Microsoft Outlook can now be chosen in Preferences as the application used by Aperture for emailing photos
Fixes a problem that could cause Aperture, running on OS X Lion, to quit unexpectedly when using brushes to apply adjustments
Loupe now correctly displays magnification levels between 50-100%.
Fixes an issue that could cause Aperture, running on OS X Lion, to display the incorrect color profile on externally edited images
Import window now includes an option to delete photos from iPhone and iPad after they have been imported into Aperture
The Lift & Stamp tool now displays the correct cursor icons when being used in Split View and Viewer only modes
The update is recommended for all users of Aperture 3.
For detailed information on this update, please visit this website: http://support.apple.com/kb/TS2518