Extra Spell( Complete Arcane, p. 79)
You learn an additional spell.
Caster level 3rd,
You learn one additional spell at any level up to one lower than the highest level of spell you can currently cast. Thus, a 4th-level sorcerer (maximum spell level 2nd) gains a new 0-level or 1st-level spell known with which to expand her repertoire. For classes such as wizard that have more options for learning spells, Extra Spell is generally used to learn a specifi c spell that the character lacks access to and would be unable to research.
You can gain this feat multiple times. Each time, you learn a new spell at any level up to one lower than the highest level of spell you can cast.