cast it when in close proximity level with undead. I dont know the exact statistics, but depending on your level and the undead things level, it could be turned in fear or even destroyed.
'My pantaloons are full of weasels. Inform the Queen, so that she might shoo them away. Here we go 'round the mulberry bush. Go monkey GO!'-Wanev
Have you ever heard any more inspiring or logical words? I sure haven't.
Turning undead depends on Charisma. If you have a min-maxed cleric with 3 Charisma then they probably won't even be able to turn a Manchester United supporter, let alone any udead.