On April 3rd, 1973, Motorola engineer Marty Cooper placed the first public call from a cellphone. In midtown Manhattan, Cooper called Joel Engel — head of rival research department Bell Labs — saying "Joel, this is Marty. I'm calling you from a cell phone, a real handheld portable cell phone." The call was placed on a Motorola DynaTAC 8000x, which weighed 2.5 pounds, a far cry from today's 4-ounce handsets.

The Verge, who posted this news also has an interview with Marty Cooper, the father of the cellphone at http://www.theverge.com/2012/2/20/2811861/marty-cooper-interview.