Apple has posted Software Updates for the MacBook and MacBook Pros, bringing the Firmware to version 1.1 on both line-ups.
This update addresses a responsiveness issue on MacBook and MacBook Pro notebook computers. Some MacBook and MacBook Pro systems may occasionally experience a temporary suspension of keyboard input which can last a minute or longer. The Mac OS X 10.5.1 update is required before installing the MacBook, MacBook Pro Software Update 1.1.
The update is available either through the Software Update utility or through Apple's support web site [1].