Is film available for the old Polaroid Electric Zip cameras made in the 1970s?

Short answer: The film is no longer being produced. 

Polaroid produced a variety of instant film for cameras like the Zip and the ever popular Land cameras.  Examples are: 669 (color ISO 80) and 667 (B&W ISO 3200).  Polaroid stopped producing the film and sold the rights to Fujifilm who stopped making their F100 film several years ago.

There are a lot of this film available on eBay.  All of this film has expired, however, if it has been kept in a refrigerator all its life, then it's likely to be okay.  Refrigeration greatly slows the degradation of the film.  If not, then the film will have a heavy magenta or cyan color cast.  Considering that the film can run anywhere from $25~$150 for a pack of 8 shots, I would avoid buying any of it unless you can confirm that the film has been kept in a refrigerator. 

Why on earth would you bother. Crappy camera, crappy EXPENSIVE pictures. Use your phone an have pictures printed at Walgreens, CVS etc., etc.

This camera used the so called size 80 packfim (square) which is not available anymore. There were no substitutes by other companies like Fuji. So the only chance you have is get some extremely outdated original Polaroid size 80 film which might or might not work and will cost an arm and a leg ( if you can get it) developing chemicals are likely to have dried out.

All in all it would be a challenge with, to put it optimisticlly, uncertain outcome.

Sorry to say. It looks decorative on a shelf, though, with all the red and black