Sysprep: naming computer according to MAC-adress

Hi,

I´m in the process of rolling out a lot of XP PC's that will be set up using
SYSPREP.
One of the things I'd like to to is make the PC's mac-adress it's
computername.
Is there any way to have SYSPREP automate this?
I know it's possible to have SYSPREP generate a random computername. the
other option is to specify according to a list of names. Leaving it blank
will prompt for a name during mini-setup.
How would I extract the mac-adress of a specific pc and use it in SYSPREP?

Any help or guidance would be greatly appreciated.

Thanks,

Jacob