Simply install too many items and you should be able to place spawners, sadly they r all pigs, which become boring after a while, to change this simply locate your .minecraft folder and you should see a txt file named too many items, open it and you should see al ot of strange words and lots of things like Save:1Save:2 and so on, second from the bottom you should see "spawner: Pig", simply change Pig to whatever mob you want, (even creepers) be sure to spell it properly and with a capital. I've done creepers, ghasts, silverfish, blazes and wolfs. Enjoy: zeno :D...