First, you need bukkit. Install the Essentials Spawn plugin and type "/setspawn" in the server to set the spawn.
Chat with our AI personalities
You need singleplayercommands. On teh command bar do /setspawn
The spawn area in a server is protected. (A radius of 33 blocks). Have them move more than 33 blocks away from the spawn point, and then they will be able to build.
the best server to grief is 69.175.5.196 nothing is protected not even spawn
Use the hamachi server.
You need the server software first. Once you get the server set up, you can copy your save to the server.