Staple is a framework for managing and configuring the boot of diskless computers. It recognizes the host and the root filesystem (and can be extended to recognize other aspects of the system) at early stage of the boot, and configures the machine appropriately, so it will boot as desired (appropriate drivers, security configuration, etc.).

Staple is available as open source at: http://code.google.com/p/stapleboot. Currently works on linux, and to some extent on macs.