Setting up a Minecraft server on Mac OS X is no different from setting it up on windows. Just follow these simple steps to create your own private server.
Minecraft Server Guide
Step 1| Updating Java
Updating Java in Mac OS X is very easy, Mac has its own version of Java, which can be updated from Apple Menu > Software Update.
Step 2| Setting up Minecraft Server
First download this Minecraft_server.jar file and place it inside a folder.
Now you must run it through the “terminal”, first navigate to the folder where you are keeping .jar file (use this command as an example)
Then use this command
java -Xmx1024M -Xms1024M -jar minecraft_server.jar
After running the server for the first time, it will generate some files in the folder.
To change server settings/rules edit server.properties file.