Bukkit

permissions:
mobspawners.getdrop
mobspawners.getspawner

commands:
/getspawner <mobtype>

drops:
when breaking a spawner that has been put it drops the spawner
with the mob type information, so you can place it on other place.

placing:
just need the spawner and as simple as place any block it will be
setup the spawn with the entity type set.