According to IGN,
However, it turns out that the navigation controller isn't a necessity. If you want to, you can hold your SixAxis or DualShock 3 controller in your left hand and the PlayStation Move in your right and not miss a beat. The navigation controller does have a few extra buttons on it, but the ones you need to play games – L1, L2 and an analog stick – are all right where you need them on the SixAxis/DualShock 3's left side.
I think a lot of us speculated on this fact but I guess it's true.
That takes $29.99 off the cost of the Move controller, unless you decide to opt in for the luxury of a smaller controller.