The Oriental Adventures book has spells Lesser Spirit Ally, Spirit Ally, and Greater Spirit Ally. However, they summon spirits for a longer duration (you summon them and then negotiate with them to have them perform a service for you; the time it takes to do that service apparently isn't limited to a set amount of time, so long as it is just one single service or task. I don't know if that's the sort of thing you're looking for or not.