Apple’s released a couple of updates:

MacBook Pro Software Update 1.2 is for the 2.2/2.4 GHz versions and improves graphic stability. It’s a 14.4MB download you can get via Software Update or directly here.

iMac Software Update 1.2 repairs the random freeze issue plaguing some 20- and 24-inch iMacs running on 2.0/2.4/2.8GHz processors. It also provides the usual “important bug fixes”. It comes for two species - Tiger is 13.3MB and can be had here, and for Leopards it’s 21.6MB and can be had here. Alternately, you can get SU to do it for you.