We wrote about new iMacs having a screen freezing issue (first time, second time), and in the four weeks or so since Apple has clearly been at work on the problem.
And now, the solution: some software downloads for you to apply. There's a version for those sluggards running Tiger, and one for the bleeding-edge types running Leopard.
However, reading the comments on The Unofficial Apple Weblog, it seems not everyone is satisfied:
This hasn't fixed the freezing issue. In fact, 30 seconds after restarting once the update was complete it locked up again.
We'll wait and see. Let us know how it goes for you...