| Drejk |
Actually the inspire courage grants competence bonus to attack and weapon damage rolls. Which means that anyone maing attack roll gains bonus to attack roll. Anyone making weapon damage roll also gains this bonus. Spells often use attack rolls (benefiting from attack bonus) but unless they produce effects that are considered weapons they don't benefit from damage bonus. Using a spell from wand or casting it oneself is works the same for this consideration.
Which spells are considered weapons for purpose of this ability?
Rays an anything that produces a weapon-like effect: relevant FAQ entry.