A wheeled camera dolly can add smooth tracking motions to your smartphone opus, but if you were hoping to include a dramatic vertical reveal, you'll need the Mobislyder which instead uses a smooth ball-bearing track system.
Designed specifically for use with smaller cameras, the Mobislyder includes articulated mounts that either screw into the thread mount on the underside of your camera, or clamp onto thinner devices like smartphones. It can be laid on the ground for more traditional shots like zooms or dollies, but can also be leaned up against a wall, expanding the number of smooth, stabilised moves you can perform.
The $US128 base unit comes with five different mounts actually, so the odds are pretty good you can find some way to attach your device. But I think the 14 inches of track is really short, so I'd suggest springing for the longer 26 square inch (168sqcm) spare rail as well, so as not to limit your creativity. I guarantee Kubrick would have done the same. [Glidetrack via Ubergizmo]