Starting a server

[yoyoman]

I am trying to start a minecraft server for me and my friends but I keep getting this error

Hidden/Spoiler:

[INFO] Starting minecraft server version Beta 1.4_01
[INFO] Loading properties
[INFO] Starting Minecraft server on *:25565
[WARNING] **** FAILED TO BIND TO PORT!
[WARNING] The exception was: java.net.BindException: Address already in use: JVM_Bind
[WARNING] Perhaps a server is already running on that port?

what should I do?

Edit
I have tried to do it over and over again but I kept getting the same warnings. thanks

[Twilight_Warrior]

You need to forward port 25565 on your router.

[yoyoman]

What does that mean.

[Twilight_Warrior]

It means you need to open up a part of your network so that users can connect to your IP address.

Use this: http://portforward.com/help/portforwarding.htm
To get a better understanding of port forwarding.

And this: http://portforward.com/
To find a tutorial on how to forward a port on your specific router model.