Nope, no stereo music on the iPhone. EVER.
There is a reason the first gen. didnt have it, and no one knows what it is. Battery life is the only excuse I've heard, but with the new battery, that argument goes right out the window.
I've kept my iPhone nice and unjailbroken, but if someone can figure out how to turn on this feature, I'm going for it. Might anyway, rather than wait an unspecified time limit until 2.0 is released.