Using old hardware to make a torrent box.

I build a small wiring closet in an empty closet in my house with my modem and router. I plan to also put a small machine to download torrents for me to.

The specs will most likely be crap I have in my basement:
Pentium III ~450Mhz and matching ASUS motherboard. Probably very little RAM, assume a single stick of 128mb. Generic video card, not even sure if it will be AGP. I'm probably going to have to buy a small harddrive around 20-40Gb. The machine won't have much cooling since it'll need to be quiet.

The features I'd like are webserver and torrent client+web interface. I want the most lightweight OS and software.

What are you suggestings?

>>9
Well according to Google there's ABC: http://pingpong-abc.sourceforge.net/ which appears to be designed for winders, but it claims to have a web interface. Further down the results page there's a plugin for Azureus http://azureus.sourceforge.net/plugin_details.php?plugin=webui that gives you a web interface. I dunno if it would be advisable to run Azureus on a low spec machine though (lol java)