Mike,
Thanks for the quick response...
It's the dual functionality that makes it a little difficult. When quickly pressed and released, it's latched on. When pressed and released quickly again, it's turned off.
When the button is pressed and held down, it becomes a momentary pushbutton, that is push to talk. When released, the circuit is no longer active.
I've attached a drawing, that hopefully will help explain...
I'm a total newbie, so I'm not too familiar with a lot of this, but I've been told that a PIC would be the best option.
One of the products I'm familiar with has the functionality that I want in a button. Their schematic diagram shows that they use a microcontroller to do the job.