Apple has issues a few software updates yesterday and today, including updates for the newly released iMacs. Use Software Update or visit the download pages.
Aperture 1.5.4 Update: required for compatibility with iLife '08. This update is recommended for all Aperture users. (download page)
Front Row 1.3.1: provides for improved iPhoto compatibility. (download page)
iPhoto 7.0.1: addresses issues associated with publishing photos from an upgraded library to .Mac Web Gallery. (download page)
iMac Software Update 1.0: provides important bug fixes and is recommended for 20-inch and 24-inch iMac models with 2.0, 2.4, or 2.8GHz processors. (download page)
Mac Pro SMC Firmware Update 1.1: The SMC Firmware Update adjusts fan behavior in the Mac Pro. After this update has completed successfully, your SMC Version will be 1.7f10 (Mac Pro), 1.5f3 (Mac Pro 8-core). (download page)