Apple has released MacBook, MacBook Pro Software Update 1.1 which 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.
MacBook, MacBook Pro Software Update 1.1 is availbale via Software Update and also as a standalone installer.
More info and download link (979KB) here.