Hi, I'm building a windows media center and am looking for a
motherboard that satisfies the following requirements:

1) micro ATX, socket A
2) Will work with a mobile athlon XP
3) Allows me to adjust the CPU voltage down, to 1.2V or even lower
4) Allows me to adjust the clock speed, so I can slow the chip down
5) Has built-in networking (10/100Mbps is fine)
6) Has built-in audio, with SPDIF connector
7) I would prefer if it uses the nforce2 IGP chipset, which will
provide the networking and audio, as well as graphics. If it does, I
would also hope it provides s-video output. This is not an absolute
requirement, since I can purchse a separate video card, but is
preferred (or, if the MB is particularly cheap, leaving excess money
for a video card).
8) I can purchase it (e.g. not discontinued or impossible to find)

As you can tell, I plan to use a low voltage and slow down the clock
speed, so that the CPU runs very cool and hence doesn't need much in
the way of fans.

I found this to be somewhat useful:
http://www.silentpcreview.com/article69-page1.html

Thanks

There are lots of utillities that will slow down your processor on this site:
http://www.majorgeeks.com/downloads14.html

Once you slow it down I don't think that you would need to adjust the
voltage down to compensate. To low and the system could become
unstable. This voltage adjustment does however apply when you are
over-clocking.