Saeviomagy
Adventurer
The problem with this is that it basically means that in order to use a spell, you need to have a skill.Ottergame said:I'd go with Knowledge: Planes for that.
It hurts sorcerors quite a bit, because they don't have k

I'd suggest that knowledge of the spell automatically conveys knowledge of the keys for widely known planes. Specifically ones home plane and the plane of ones diety, or possibly some alternate plane in the case of non clerics (ie - the negative plane for necromancers, elemental planes for elementalists etc).