Devoted Magi (3.5e Feat)
From D&D Wiki
Devoted Magi [General]
Your devotion to the righteous path harmonizes with your innate arcane abilities.
Prerequisite: Access to Paladin spell list, Ability to spontaneously cast arcane spells.
Benefit: Your Paladin casting ability and spells per day are based off of your Cha modifier instead of your Wis modifier. Once a day per spell level, you may prepare a Sorcerer spell known to you in a Paladin spell slot of the same level. This spell may be cast as a swift action and without somatic components. Once per day per spell level, you may spontaneously cast a spell from the Paladin spell list as a Sorcerer by using up a Sorcerer spell slot three levels higher than the Paladin spell level.You may multiclass freely between Sorcerer and Paladin but the normal multiclassing XP penalties are not lifted.
Normal: Paladin spellcasting is based on Wis. Paladin and Sorcerer levels cannot share spells. A Paladin who multiclasses cannot again take a level in Paladin.
Special: By taking this feat, if you cast arcane spells or use spell-like abilities of the Necromancy school, that cause fear or that use negative energy as it counts as violating the Paladin code of conduct. If the prerequisites for this feat cease to be met, this feat will become inactive until they are restored. This feat cannot be taken more than once.