Terminal Problem (Minecraft)

This is what shows in my terminal:

13:01:07 [INFO] Starting minecraft server version 1.5.1

13:01:07 [INFO] Loading properties

13:01:07 [INFO] Default game type: SURVIVAL

13:01:07 [INFO] Generating keypair

13:01:08 [INFO] Starting Minecraft server on *:25565

13:01:08 [WARNING] **** FAILED TO BIND TO PORT!

13:01:08 [WARNING] The exception was: java.net.BindException: Address already in use

13:01:08 [WARNING] Perhaps a server is already running on that port?

How do I fix this issue???