Intel Mac EFI Firmware Updates
Apple released three firmware updates which deliver EFI with BIOS support for the Intel Macs. These do not appear automatically via the Mac OS X Software Update mechanism, so you must download and install them manually.

iMac (Intel) Firmware Update 1.0.1 (2.8MB) updates iMac computers with Intel processors only.
MacBook Pro (Intel) Firmware Update 1.0.1 (2.8MB) updates MacBook Pro computers with Intel processors only.
Mac mini (Intel) Firmware Update 1.0.1 (2.8MB) updates Mac mini computers with Intel processors only.
Firmware Restoration CD v1.0 (8.7MB) can restore the firmware of an Intel-based iMac (early 2006), Mac mini (early 2006), or MacBook Pro (early 2006) to original factory condition. It can only be used to restore the Firmware after an interrupted or failed update.

The following Knowledge Base article provides more information on the firmware updates:
http://docs.info.apple.com/article.html?artnum=303364