This crap changes every 2 days, but as of Minecraft 1.8.1 and the associated CraftBukkit recommended build on 10-2-2011, you can do the following.

====== Install ======

Get (or update) minecraft:
  mv -f minecraft_server.jar minecraft_server.jar-`date +%Y%m%d`
  wget https://s3.amazonaws.com/MinecraftDownload/launcher/minecraft_server.jar

Get (or update) craftbukkit:
  mv -f craftbukkit-0.0.1-SNAPSHOT.jar craftbukkit-0.0.1-SNAPSHOT.jar-`date +%Y%m%d`
  wget http://ci.bukkit.org/job/dev-CraftBukkit/promotion/latest/Recommended/artifact/target/craftbukkit-0.0.1-SNAPSHOT.jar

Get the Essentials plugin from [[http://forums.bukkit.org/threads/gen-sec-econ-tp-admn-essentials-v2-6-2-a-collection-of-useful-commands-and-features-1185.15312/|this forum post]] or [[http://ess.khhq.net/wiki/Main_Page|this wiki]].  To install the core pack and group manager, as of right now you can do:
  cd plugins
  wget http://tiny.cc/EssentialsZipDownload
  unzip EssentialsZipDownload
  rm EssentialsZipDownload
  wget http://tiny.cc/EssentialsGMZip
  unzip EssentialsGMZip
  rm EssentialsGMZip
  
For full control, add your name to "ops.txt", e.g.
  echo "myname" >> ops.txt

If you installed Essentials Group Manager above, you can configure it by changing "''plugins/GroupManager/config.yml''" or "''plugins/GroupManager/worlds/world/*.yml''".  To confirm, editing these files by hand sucks, as does the usability of CraftBukkit in general.  ENJOY!
====== Launch ======
In these scripts, set M to the amount of RAM to allow, in megabytes.

Vanilla server:
  #!/bin/sh
  M=350
  java -Xmx${M}M -Xms${M}M -jar minecraft_server.jar nogui
 
CraftBukkit:
  #!/bin/sh
  M=350
  java -Xms${M}M -Xmx${M}M -jar craftbukkit-0.0.1-SNAPSHOT.jar nogui