Heres some information on this technique and how to achieve this technique:

Zoom burst is a photographic technique, attainable with zoom lenses with a manual zoom ring.

Using the technique involves zooming while the shutter is open with a relatively slow shutter speed, generally below 1/60th of a second. For this reason low light or small apertures are required. It is also possible to achieve a similar effect with either computer software likeAdobe Photoshop (after the photo has been shot) or a photographic filter. In these cases the shutter speed can be as fast as necessary.

Photographs taken with this technique are characterized by blurred streaks emanating from the center of the photograph. The effect is nearly identical to a motion blur image in which the camera is traveling towards the subject. For this reason the zoom burst is typically used to create an impression of motion towards the subject.

Heres a few examples on this technique: