I don't understand your question, but the Cydia version is just a GUI for the iPhone. Google Voice is from google, and you need an invite from them. voice.google.com can let u go into a waitlist for an invite.
free from Cydia np but you need a invite I registered 2 myself when I did it I gave one away. it took me about a week to get a invite after I requested one. this is the link (just click where it says request a invite!) hopefully we helped oh the app from cydia is GV mobile