Here is a portion of the CBS radio broadcast of Super Bowl 1 between the Packers and Chiefs, courtesy of RadioTapes.com. The clip of about 17 minutes was recorded by WCCO-AM in Minneapolis. It mostly covers the pregame, but also contains a few plays of game action along with a postgame recap.
The announcers are Jack Drees and Tom Hedrick. During the clip, Hedrick refers to the game as the "Super Bowl", mentions the pointspread, and tries to rationalize the fact that there were numerous empty seats in the Los Angeles Coliseum that day.