Apple has posted Bluetooth Firmware Updater 1.1 to its site. The updater adds improved performance and additional key commands during startup. From Apple:
About Bluetooth Firmware Updater
Provides improvements in the update installation process, better performance when waking the computer from sleep, and support for additional key commands during startup.The Bluetooth Firmware Updater is for D-Link USB Adapters (revision B2 or later), and Apple internal Bluetooth modules on PowerBooks and PowerMacs. This firmware update will improve connectivity between the computer and the Apple Wireless Keyboard and Mouse. Use this updater for the modules specified above; this updater is unsupported with any other Bluetooth modules.
Important: Applying this firmware updater to a D-Link USB to Bluetooth adapter will make it incompatible with non-Macintosh systems.
You can find more information about the Bluetooth firmware update at Appleis site. The update weighs in at 1.4MB, and is compatible with OS X 10.2.8 and OS X 10.3.3.