Linux Magic Jack?

[mike Enriquez]

I  saw  a demo of Magic Jack which a USB thumb drive like device that
lets you plug in a telephone jack and make all your phone calls via the
internet.It claims to work only on windows. 
They claim that the annual fee is $20.00. Does anyone on the list know
if this is available on Linux or something else exist that is similar.
Boy, I like the price of $20.00 per year to make all my phone calls.
Thanks 
Mike Enriquez