Consider a Skype paid subscription - about $3 a month, but usually works better than GrooveIP, and should continue working even after GrooveIP dies down. Skype will allow unlimited calls to other landlines/cellphones within US (with the paid subscription) - works on desktop/laptop too.
(Every now and then, you can get a yearly subscription for half price - no guarantees of course)
(Every now and then, you can get a yearly subscription for half price - no guarantees of course)