Apple just released iPhoto 9.2, which brings Photo Stream support as its main new feature, but also include some other fixes and enhancements as well:

iPhoto 9.2 supports compatibility with iCloud and iOS 5. This update also addresses minor stability, performance and compatibility issues, including:

 

• Left and right swipe gestures can now be used to navigate between photos in Magnify (1-up) view
• Previously imported photos are now displayed in a separate section of the Import window
• Book/calendar themes and card categories can now be selected using a pop-up menu in the carousel view
• Resolves an issue that could cause some pages of books to print incorrectly
• Rebuilding a library now correctly preserves saved slideshows and books
• The update is recommended for all users of iPhoto '11.