Steve Jobs introduced the new Unibody Aluminum MacBook in two basic configurations. The 2.0 GHz and the 2.4 GHz model.

According to the announcement and the tech specs, the 2.4 GHz model has one feature the other doesn’t. It is the backlit keyboard.

Contrary to the announcement and the tech specs, Apple Store Online offers backlit keyboards on all Unibody Aluminum MacBook. Most likely this is a typo.