Farming using Mob Spawners in Minecraft

Most mob farming techniques use a stream of water which collect all the monsters in the room to a central point, and then drowns them by pulling them underwater. Some other ways to kill them are:

• Pushing them via a water current into cacti
• Using lava to kill them
• Making them fall really far so they die from the impact

Just as a note, most people just build enormous completely dark rooms (like this one) to farm mobs rather than using the actual mob spawner blocks.

Here are some screenshots from the link above:

      I found a really neat video a while ago of a Mega Mob Factory someone had made for farming Ham. I'm sure you could do the same with a mob of creepers.

      This works on the same principle as most mob farms: it uses water currents to trap pigs and pull them underwater, drowning them. All of the spoils end up at a singular point below the structure, that can be accessed by a ladder.