What UESP says regarding Oblivion is "Your Spell Effectiveness will be reduced if you wear armor. There are two types of armor: light armor and heavy armor. It doesn't matter which one you actually use as far as your skill is concerned. Your overall Spell Effectiveness while in armor, either light or heavy, cannot exceed 95% regardless of your skill in that armor. The skill rating for the armor you wear must be at least Journeyman rank to maintain 95%; lower ratings than Journeyman results in lower effectiveness. 100% Spell Effectiveness can only be achieved if you are not wearing any armor"
They say the penalty is just tied to your skill in the armor you are wearing in Oblivion. I haven't heard exactly what the Skyrim system will be.
alright thanks, im just trying to figure out if i were to make a spellshield type of class (due to the great shield skills) what type of spell effectiveness i would be lookin at for myself. i assume it will generally end up working similar if not the same as it had in oblivion. but hey, il just have to wait and see to be exact i guess.