The conference colloquium by Dr Zweig is available as a video download.
But, be forewarned, it is BIG! (~136Mbytes)

http://www.physics.miami.edu/~cgc/zweig-presentation-300kbps.avi

To play it one needs the DIVX codec http://www.divx.com ,
or else one needs to install the VLC player http://www.videolan.org .

An earlier, written version of the colloquium is available here.

A scan of Zweig's 1964 CERN-TH-412 report is here.