Dick Tracy was the very first one to use them; back in the 1940’s when it reached the mainstream media, through the Chicago Tribune’s pages.
Since then, some companies presented prototypes of wrist phones, a couple of them even launched some models, but all of them were big, heavy things. Nothing you would like to walk around with.
But the companies are still trying, here are some models, like the BenQ Siemens snake model, the LiteON bracelet, the Nec Tag and finally the coolest one IMHO, the Nokia Icon.
LiteON
BenQ-Siemens
Nec Tag
Nokia Icon