Anathema is a 9th level spell that you may only cast on a member of your own faith.
The range is "does the other guy exist and is he lower level than me?" If that holds true, and the DM doesn't say no...
The target permanently loses the ability to cast Divine spells, and to draw upon his deity's power for any sort of divine-sourced class features (including, explicitly, the ability to turn or rebuke undead.)
Members of the same faith aren't allowed to talk to, look at, or acknowledge your victim. If they die, they immediately are sent to the Wall of the Faithless in Faerun.
It may be removed by them either changing their faith (FIND A NEW GOD, HERETIC), or by receiving an atonement spell from a spellcaster of higher level than you.
To clarify: a spellcaster of higher level than you, who instinctively knows to ignore that heretic over there.
I swear, this spell is just dickish in so many ways...
EDIT:
Advice is such a fun spell; it's Suggestion, except without a wordcount limit and able to force people to kill themselves.
Sure, they get a second save, but that is highly abuseable...