CPU and environment: You need a machine that's got enough processor to spare for the game. I was running a 2.4 kernel Debian on a P200 with 192MB RAM, and it worked great, so it's not that hungry - but you can't have high priority things preempting MAngband if you want a smooth game experience. Therefore... multimedia or programming (compiling) use of the computer is a no-no. That includes Flash, DVDs, and all that.
Bandwidth: A dedicated 60-80 KB/sec upstream and downstream should be enough for a server. Typical bandwidth usage (if I remember right) maxes out at around 6-10KB/sec per user.
Uptime: You want a server that can be online in the wee hours of the morning, because this game is played by people from all over the world.
Knowledge: You should know how to set up cron jobs for log maintenance or starting the server upon reboots, and you definitely have to be comfortable with UNIX filesystems and permissions. Simple shell scripting is a must-have skill as well. Learn to use grep and a decent editor (vim, emacs, crimson editor?).
So, if you can spare all that... maybe running a server is for you! Get the sources, compile, and try getting it running - don't make it public until it is stable. Here is my source:
http://www.danlib.net/share/MAngband/bm ... .4_src.zip