automatically turning off power and shutdown??

[<debuser@platinum.globalmart.com>]

In Windows, when I shutdown the computer, it automatically turns off the
power.  I believe it's something in the BIOS that allows this as not all
machines running Windows do this. Is there a way to make Linux do the same
thing?  I like listening to MP3's as I go to sleep and would like have it
shutdown and turn off the power after 30 minutes so that it is not
generating heat and I don't have to hear the fan in the middle of the
night.

Thanks,

Gerry