I saw a demo of the latest about-to-be-released version of Sun Installation Assistant (SIA) the other day, its an enhanced version of the existing tool which ships with many of our x64 systems and facilitates easy installation of Linux and associated drivers/option cards. The screenshots say it all - we will shortly be doing Windows too!! (click to enlarge images):
OS Choices - Linux and Windows (lists those supported by platform)
This update will be released with the next versions of the software updates for each platform, starting in May 2007.