QUOTE (Street Magic @ re: "Conjuring an Ally," pg. 104)
Step 3: Choose Powers
Each ally spirit automatically starts with the powers of Astral Form, Banishing Resistance, Realistic Form, Sapience, and Sense Link for free. Each also receives one additional power per point of Force, chosen from any powers available to spirits the initiate may conjure. The initiate may give the ally extra powers available to spirits his tradition can conjure at a cost of 5 Karma each. If the magician chooses the Elemental Attack, Energy Aura, or Engulf powers, he must specify what form the power takes.
Step 4: Choose Skills
All ally spirits automatically start with the skills of Assensing, Astral Combat, Dodge, Perception, and Unarmed Combat at a rating equal to their Force. The conjurer may grant the spirit additional skills at a rating equal to Force from among those that he possesses or that the ally needs in order to use its powers or innate abilities (such as Exotic Ranged Weapon if it has the Noxious Breath power, or Counterspelling if it has the Magical Guard power) at a cost of 5 Karma each. Ally spirits may also be given the Flight skill, assuming it fits the spirit's form. Allies may never possess skills from the Conjuring skill group.
What I get from this is that you can give your ally the Skill power, as long as your tradition allows you to summon guardian spirits. You may also simply grant the ally any combat skill that you know, at a cost of 5 Karma per skill.