Instructions
Log in to your "Minecraft" account with your user name and password. Select "Multiplayer" as your game type and enter the IP address of your server. Click the "Connect" button to enter the world.
Type "T" to open the console in the game. Use the "/give" command to give your character a monster spawner. The proper syntax for the command is "/give playername datavalue quantity" where playername is the target of the command, datavalue is the unique reference ID assigned to the item and quantity is a number that expresses how many of the item to give. For example, entering "/give Player1 52 10" would give Player1 10 spawners. The monster spawner has a data value of 52.
Press "Enter" to give your character the specified number of spawners. Items that receive the "/give" command appear on the ground immediately in front of the target. Walk over the items to automatically pick them up. You can only pick up as many spawners as you have empty slots in your inventory. Equip the spawner using your mouse's scroll wheel and right-click on an empty surface to place it in the world.