Innate Spell( Tome and Blood: A Guidebook to Wizards and Sorcerers, p. 41)
You have mastered a spell so thoroughly you can now cast it as a spell-like ability.
Choose a spell you can cast. You can now cast this spell at will as a spell-like ability once per round, without needing to prepare it. One spell slot eight levels higher than the innate spell is permanently used to power it. If the innate spell has an XP component, you pay the XP cost each time you use the spell-like ability. If the innate spell has a focus, you must have the focus to use the spell-like ability. If the innate spell has a costly material component (see the spell description) you use an item worth 50 times that cost to use as a focus for the spell-like ability. Since an innate spell is a spell-like ability and not an actual spell, a cleric cannot convert it to a cure or an inflict spell. Divine spellcasters who become unable to cast divine spells cannot use divine innate spells.
You can choose this feat more than once, selecting another spell each time. You have to pay the costs in spell slots, focuses, and material components for each innate spell you acquire.