How do I spawn Enderdragons in Minecraft?

If you use Single Player Commands, You get about a hundred useful mods in one. Once installed, just type

spawn 63

I think you can do it with MCEdit by placing a spawner and changing the id appropriately.

There is a good reason why Enderdragons spawn only in the End. If you made one spawn in the overworld, it would most likely wreak havoc on your structures and terrorize your world until you kill it, similar to the newly added Wither. However, if you really want to spawn it, install Single Player Commands and type /spawn enderdragon.

You can do it through the Mob Spawner mod . You have to have the latest beta version to do it though.

Or Watch this video I have found for it. [its rather slow, but everything is there] The author provides that mod in the notes and the dragons are located in The End area.