i dont know how to do it do u have to bye it? and how u install World of Minecraft?

ill help yo guys how to make one NOW! just do this this this this and this (LOL). but now serious: (this work on mac AND windows)
first you downloud minecraft_server.jar from minecraft.net and openit in DOWNLOADS thats the only place where it work :/. then you close it agan and a lot of files has been spawned.. but first you heve to go at this: https://secure.logmein.com/products/hamachi2/download.aspx
download the UNMANGED one. and dont vergot to agree the conditions of use (under it) then you install the logmein hamachi2 and open it up:
you create a network called what you want just like (you)'s minecraft server or something if you want it preative: make a password thats very long.
if you want to make a public one just do 123.
jou need to download the windows version on windows. its the SAME! and download the minecraft_server.EXE
then you go back at the files.
you need to open up server proppety's with textedit or word
ull see this:

#Minecraft server properties
#Wed May 04 17:34:58 CEST 2011
level-name=world
hellworld=false
spawn-monsters=true
online-mode=false
spawn-animals=true
max-players=20
server-ip=
pvp=false
level-seed=
server-port=
allow-flight=false
white-list=fasle

you can allow and delow things to do this:
false= no
true= yes
`PUT ONLINE MODE TRUE!
if you dont yours server wont work!
dont put enything in server ip
and put 25565 in server port
you can turn on-off monsters/animals and pvp and nether world+white list.
it heve to be THIS: then

#Minecraft server properties
#Wed May 04 17:34:58 CEST 2011 (and if you edit this it wil mess with something i think)
level-name=world
(dont remove only levels with the name wold will work)
hellworld=(choose self)
spawn-monsters=(choose self)
online-mode= (MUST BE TRUE FOR WORKING!!!)
spawn-animals= (choose self)
max-players= (choose self)
server-ip= (MUST BE EMPY!)
pvp= (choose self)
level-seed= (not needed)
server-port=25565!
allow-flight=(choose self)
white-list=(choose self)

then you can mape players admin in opstxt.
just put players usernames inside.
whitelist and bannd in the same! just put names down!
if you dont want to spawn items MAKE NOBODY OP!
ops can spawn items (answer for grayskull246)
SAVE ALL THE TXT'S!!!! (op's.txt bannd.txt white-list.txt)
DONT CHANGE THE NAMES OF op's.txt bannd.txt white-list.txt
then you openup minecraft_server.jar agan. it will start up and say:
for help typ help or ?
typ ? in the bar under it.
itll show you all the commands for admins.
You dont need to download plugins for spawnin items now!
then you put in the ip that you heve from hamashi: (x.xxx.xxx.xx)
with :25565 on the end.
AND YOU R IN YOUR OWN MINECRAFT SERVER!!!!!!!!!!!!

xtra's:

How to spawn items:
/give (somebody ONLINE) (id) (amount)
find ite id's here: http://www.minecraftwiki.net/wiki/Data_values
(help use the crtl+f thing to find id's faster)

how to teleport: /tp (somebody online) (somebody online)
itll tp the first one to the second one.

can i deadmin somebody?: /deop (player)

ill find more if you type ? in the console

how to join?
download hamachi>network>join an exsisting network> network name and pass> connect> minecraft beta> multiplayer> your ip.

GOOD LUCK!

on windows is it minecraft_server.exe in place of minecraft_server.JAR

u cant turn out rain/thunder :/ i hope notch will make that. :l