Well, Civanator, please disregard my requests about other polls in the "what should we do" thread. Looks like you're already on it!!
It would seem from the map (or at least what we know of it) that the Zulus and English are a fair distance from one another. I doubt that the English could help at all (not that the AI is EVER much help - even when they're right next to the enemy). Plus, it would probably take some cash or a tech to convince them as we've been at war for a while.
I would just assume make peace for now and wait for a chance to strike.
Let's keep in mind that the English have the Great Wall, so attacks against them should be made with caution until Metallurgy.
UPON EDIT: With no vote for "make peace" I chose other.