Apple has released three updates this week, mainly firmware updates as well as a compatibility update for QuickTime.

Keyboard Software Update 1.2

Install this software to take advantage of your aluminum Apple Keyboard's special features.

Compatibility Update for QuickTime 7.2

This update delivers increased compatibility with iLife.

iMac Software Update 1.1

This update provides important bug fixes and is recommended for 20-inch and 24-inch iMac models with 2.0, 2.4, or 2.8GHz processors.

The updates weight respectively 5.1MB, 18.1MB and 35.3MB. They are available either through the Software Update utility or through Apple's support web site [1].