The battery update is available immediately via Software Update or downloadable
http://www.apple.com...ryupdate12.html
Note: The factors causing the performance issues do not present a safety risk. You may continue to use your current battery.
This battery update should be run on all MacBook and MacBook Pro computers and extra batteries that were purchased between February 2006 and April 2007.
If, after you have installed the battery update, your battery has any of the symptoms listed below, please make a reservation to bring your computer with its battery to your local Apple Retail Store, or contact an Apple Authorized Service Provider (AASP), or call your local Apple Support Contact Center. If Apple or an AASP determines that your battery is eligible for replacement, you will receive a new battery, free of charge, even if your MacBook or MacBook Pro is out of warranty.
For MacBook and MacBook Pro systems with Intel Core Duo processors, this program extends repair coverage on the battery for up to two years from the date of purchase of the computer.
http://www.apple.com.../batteryupdate/