It can be broken with a scoop, Mining Laser, a Vajra or Wand of Excavation. It will randomly give either an Ender princess, an Ender drone, and a mysterious comb. Like any other hive, there is a chance for the Ender Bees to be replaced by Valiant Bees.
Sometimes, in SMP, the hives will not generate. This can be fixed by giving yourself a hive. Since they are unavailable through NEI, they can be given with /give <Player_Name> 250 1 5